[PATCH] config: preserve config file permissions on edits

Subsystems: the rest

STALE3747d

9 messages, 6 authors, 2016-06-15 · open the first message on its own page

[PATCH] config: preserve config file permissions on edits

From: Eric Wong <hidden>
Date: 2016-06-15 23:01:00

Users may already store sensitive data such as imap.pass in
.git/config; making the file world-readable when "git config"
is called to edit means their password would be compromised
on a shared system.

Signed-off-by: Eric Wong <redacted>
---
 config.c               | 7 +++++++
 t/t1300-repo-config.sh | 6 ++++++
 2 files changed, 13 insertions(+)

diff --git a/config.c b/config.c
index a30cb5c..a0b6756 100644
--- a/config.c
+++ b/config.c

@@ -1636,6 +1636,13 @@ int git_config_set_multivar_in_file(const char *config_filename,
 			MAP_PRIVATE, in_fd, 0);
 		close(in_fd);
 
+		if (fchmod(fd, st.st_mode & 07777) < 0) {
+			error("fchmod on %s failed: %s",
+				lock->filename, strerror(errno));
+			ret = CONFIG_NO_WRITE;
+			goto out_free;
+		}
+
 		if (store.seen == 0)
 			store.seen = 1;

diff --git a/t/t1300-repo-config.sh b/t/t1300-repo-config.sh
index 58cd543..d87693e 100755
--- a/t/t1300-repo-config.sh
+++ b/t/t1300-repo-config.sh

@@ -1158,4 +1158,10 @@ test_expect_failure 'adding a key into an empty section reuses header' '
 	test_cmp expect .git/config
 '
 
+test_expect_success POSIXPERM,PERL 'preserves existing permissions' '
+	chmod 0600 .git/config &&
+	git config imap.pass Hunter2 &&
+	perl -e "die q(badperm) if ((stat(q(.git/config)))[2] & 07777) != 0600"
+'
+
 test_done

-- 
Eric Wong

[PATCH v2] config: preserve config file permissions on edits

From: Eric Wong <hidden>
Date: 2016-06-15 23:01:01

Users may already store sensitive data such as imap.pass in
.git/config; making the file world-readable when "git config"
is called to edit means their password would be compromised
on a shared system.

[v2: updated for section renames, as noted by Junio]

Signed-off-by: Eric Wong <redacted>
---
 config.c               | 16 ++++++++++++++++
 t/t1300-repo-config.sh | 10 ++++++++++
 2 files changed, 26 insertions(+)

diff --git a/config.c b/config.c
index a30cb5c..c227aa8 100644
--- a/config.c
+++ b/config.c

@@ -1636,6 +1636,13 @@ int git_config_set_multivar_in_file(const char *config_filename,
 			MAP_PRIVATE, in_fd, 0);
 		close(in_fd);
 
+		if (fchmod(fd, st.st_mode & 07777) < 0) {
+			error("fchmod on %s failed: %s",
+				lock->filename, strerror(errno));
+			ret = CONFIG_NO_WRITE;
+			goto out_free;
+		}
+
 		if (store.seen == 0)
 			store.seen = 1;

@@ -1784,6 +1791,7 @@ int git_config_rename_section_in_file(const char *config_filename,
 	int out_fd;
 	char buf[1024];
 	FILE *config_file;
+	struct stat st;
 
 	if (new_name && !section_name_is_ok(new_name)) {
 		ret = error("invalid section name: %s", new_name);

@@ -1805,6 +1813,14 @@ int git_config_rename_section_in_file(const char *config_filename,
 		goto unlock_and_out;
 	}
 
+	fstat(fileno(config_file), &st);
+
+	if (fchmod(out_fd, st.st_mode & 07777) < 0) {
+		ret = error("fchmod on %s failed: %s",
+				lock->filename, strerror(errno));
+		goto out;
+	}
+
 	while (fgets(buf, sizeof(buf), config_file)) {
 		int i;
 		int length;

diff --git a/t/t1300-repo-config.sh b/t/t1300-repo-config.sh
index 58cd543..3f80ff0 100755
--- a/t/t1300-repo-config.sh
+++ b/t/t1300-repo-config.sh

@@ -1158,4 +1158,14 @@ test_expect_failure 'adding a key into an empty section reuses header' '
 	test_cmp expect .git/config
 '
 
+test_expect_success POSIXPERM,PERL 'preserves existing permissions' '
+	chmod 0600 .git/config &&
+	git config imap.pass Hunter2 &&
+	perl -e \
+	  "die q(badset) if ((stat(q(.git/config)))[2] & 07777) != 0600" &&
+	git config --rename-section imap pop &&
+	perl -e \
+	  "die q(badrename) if ((stat(q(.git/config)))[2] & 07777) != 0600"
+'
+
 test_done

-- 
Eric Wong

Re: [PATCH v2] config: preserve config file permissions on edits

From: Jeff King <hidden>
Date: 2016-06-15 23:01:02

On Tue, May 06, 2014 at 12:17:14AM +0000, Eric Wong wrote:

Users may already store sensitive data such as imap.pass in
.git/config; making the file world-readable when "git config"
is called to edit means their password would be compromised
on a shared system.

Makes sense, and the patch looks good to me.

+test_expect_success POSIXPERM,PERL 'preserves existing permissions' '
+	chmod 0600 .git/config &&
+	git config imap.pass Hunter2 &&
+	perl -e \
+	  "die q(badset) if ((stat(q(.git/config)))[2] & 07777) != 0600" &&

I don't think we usually bother with a PERL prereq for running
one-liners like this from the test script, though I don't think it hurts
anything to do so.

-Peff

Re: [PATCH v2] config: preserve config file permissions on edits

From: Johannes Sixt <hidden>
Date: 2016-06-15 23:01:14

Am 5/6/2014 2:17, schrieb Eric Wong:

quoted hunk

Users may already store sensitive data such as imap.pass in
..git/config; making the file world-readable when "git config"
is called to edit means their password would be compromised
on a shared system.

[v2: updated for section renames, as noted by Junio]

Signed-off-by: Eric Wong <redacted>
---
 config.c               | 16 ++++++++++++++++
 t/t1300-repo-config.sh | 10 ++++++++++
 2 files changed, 26 insertions(+)

diff --git a/config.c b/config.c
index a30cb5c..c227aa8 100644
--- a/config.c
+++ b/config.c

@@ -1636,6 +1636,13 @@ int git_config_set_multivar_in_file(const char *config_filename,
 			MAP_PRIVATE, in_fd, 0);
 		close(in_fd);
 
+		if (fchmod(fd, st.st_mode & 07777) < 0) {
+			error("fchmod on %s failed: %s",
+				lock->filename, strerror(errno));
+			ret = CONFIG_NO_WRITE;
+			goto out_free;
+		}

This introduces a severe failure in the Windows port because we do not
implement fchmod. Existing fchmod invocations do not check the return
value, and they are only interested in removing the write bits, and we
generally don't care a lot if files remain writable.

I'm not proficient enough to add any ACL fiddling to fchmod that would be
required by the above change, whose purpose is to be strict about
permissions. Nor am I interested (who the heck is sharing a Windows box
anyway? ;-)

Therefore, here's just a work-around patch to keep things going on
Windows. Any opinions from the Windows corner?

--- >8 ---

From: Johannes Sixt <redacted>
Subject: [PATCH] mingw: turn the always-failing fchmod stub into always-succeeding

A recent change introduced new call sites of fchmod, but these new call
sites check the return value. The test suite can't get past t0001
without a dozen or so failures.

Just fake that the call was successful even though it did nothing.

Signed-off-by: Johannes Sixt <redacted>
---
 compat/mingw.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/compat/mingw.h b/compat/mingw.h
index c3859cc..7b2455c 100644
--- a/compat/mingw.h
+++ b/compat/mingw.h

@@ -89,7 +89,7 @@ static inline int readlink(const char *path, char *buf, size_t bufsiz)
 static inline int symlink(const char *oldpath, const char *newpath)
 { errno = ENOSYS; return -1; }
 static inline int fchmod(int fildes, mode_t mode)
-{ errno = ENOSYS; return -1; }
+{ /* do nothing */ return 0; }
 static inline pid_t fork(void)
 { errno = ENOSYS; return -1; }
 static inline unsigned int alarm(unsigned int seconds)

-- 
2.0.0.rc3.1741.g0520b9e

-- 
-- 
*** Please reply-to-all at all times ***
*** (do not pretend to know who is subscribed and who is not) ***
*** Please avoid top-posting. ***
The msysGit Wiki is here: https://github.com/msysgit/msysgit/wiki - Github accounts are free.

You received this message because you are subscribed to the Google
Groups "msysGit" group.
To post to this group, send email to msysgit@googlegroups.com
To unsubscribe from this group, send email to
msysgit+unsubscribe@googlegroups.com
For more options, and view previous threads, visit this group at
http://groups.google.com/group/msysgit?hl=en_US?hl=en

--- 
You received this message because you are subscribed to the Google Groups "msysGit" group.
To unsubscribe from this group and stop receiving emails from it, send an email to msysgit+unsubscribe@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

Re: Re: [PATCH v2] config: preserve config file permissions on edits

From: Erik Faye-Lund <hidden>
Date: 2016-06-15 23:01:14

On Mon, May 19, 2014 at 9:13 AM, Johannes Sixt [off-list ref] wrote:

Am 5/6/2014 2:17, schrieb Eric Wong:

quoted

Users may already store sensitive data such as imap.pass in
..git/config; making the file world-readable when "git config"
is called to edit means their password would be compromised
on a shared system.

[v2: updated for section renames, as noted by Junio]

Signed-off-by: Eric Wong <redacted>
---
 config.c               | 16 ++++++++++++++++
 t/t1300-repo-config.sh | 10 ++++++++++
 2 files changed, 26 insertions(+)

diff --git a/config.c b/config.c
index a30cb5c..c227aa8 100644
--- a/config.c
+++ b/config.c

@@ -1636,6 +1636,13 @@ int git_config_set_multivar_in_file(const char *config_filename,
                      MAP_PRIVATE, in_fd, 0);
              close(in_fd);

+             if (fchmod(fd, st.st_mode & 07777) < 0) {
+                     error("fchmod on %s failed: %s",
+                             lock->filename, strerror(errno));
+                     ret = CONFIG_NO_WRITE;
+                     goto out_free;
+             }

This introduces a severe failure in the Windows port because we do not
implement fchmod. Existing fchmod invocations do not check the return
value, and they are only interested in removing the write bits, and we
generally don't care a lot if files remain writable.

I'm not proficient enough to add any ACL fiddling to fchmod that would be
required by the above change, whose purpose is to be strict about
permissions. Nor am I interested (who the heck is sharing a Windows box
anyway? ;-)

Therefore, here's just a work-around patch to keep things going on
Windows. Any opinions from the Windows corner?

Since we use MSVCRT's chmod implementation directly which only checks
for S_IWRITE,and Get/SetFileAttributes to simply set or clear the
FILE_ATTRIBUTE_READONLY-flag, perhaps we could do the same except
using Get/SetFileInformationByHandle instead? That takes us in a
better direction, IMO. Adding full ACL support seems like a bigger
project.

If there's no objection, I'll sketch up a patch for that...

-- 
-- 
*** Please reply-to-all at all times ***
*** (do not pretend to know who is subscribed and who is not) ***
*** Please avoid top-posting. ***
The msysGit Wiki is here: https://github.com/msysgit/msysgit/wiki - Github accounts are free.

You received this message because you are subscribed to the Google
Groups "msysGit" group.
To post to this group, send email to msysgit@googlegroups.com
To unsubscribe from this group, send email to
msysgit+unsubscribe@googlegroups.com
For more options, and view previous threads, visit this group at
http://groups.google.com/group/msysgit?hl=en_US?hl=en

--- 
You received this message because you are subscribed to the Google Groups "msysGit" group.
To unsubscribe from this group and stop receiving emails from it, send an email to msysgit+unsubscribe@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

Re: Re: [PATCH v2] config: preserve config file permissions on edits

From: Erik Faye-Lund <hidden>
Date: 2016-06-15 23:01:14

On Mon, May 19, 2014 at 9:44 AM, Erik Faye-Lund [off-list ref] wrote:

On Mon, May 19, 2014 at 9:13 AM, Johannes Sixt [off-list ref] wrote:

quoted

Am 5/6/2014 2:17, schrieb Eric Wong:

quoted

Users may already store sensitive data such as imap.pass in
..git/config; making the file world-readable when "git config"
is called to edit means their password would be compromised
on a shared system.

[v2: updated for section renames, as noted by Junio]

Signed-off-by: Eric Wong <redacted>
---
 config.c               | 16 ++++++++++++++++
 t/t1300-repo-config.sh | 10 ++++++++++
 2 files changed, 26 insertions(+)

diff --git a/config.c b/config.c
index a30cb5c..c227aa8 100644
--- a/config.c
+++ b/config.c

@@ -1636,6 +1636,13 @@ int git_config_set_multivar_in_file(const char *config_filename,
                      MAP_PRIVATE, in_fd, 0);
              close(in_fd);

+             if (fchmod(fd, st.st_mode & 07777) < 0) {
+                     error("fchmod on %s failed: %s",
+                             lock->filename, strerror(errno));
+                     ret = CONFIG_NO_WRITE;
+                     goto out_free;
+             }

This introduces a severe failure in the Windows port because we do not
implement fchmod. Existing fchmod invocations do not check the return
value, and they are only interested in removing the write bits, and we
generally don't care a lot if files remain writable.

I'm not proficient enough to add any ACL fiddling to fchmod that would be
required by the above change, whose purpose is to be strict about
permissions. Nor am I interested (who the heck is sharing a Windows box
anyway? ;-)

Therefore, here's just a work-around patch to keep things going on
Windows. Any opinions from the Windows corner?

Since we use MSVCRT's chmod implementation directly which only checks
for S_IWRITE,and Get/SetFileAttributes to simply set or clear the
FILE_ATTRIBUTE_READONLY-flag, perhaps we could do the same except
using Get/SetFileInformationByHandle instead? That takes us in a
better direction, IMO. Adding full ACL support seems like a bigger
project.

If there's no objection, I'll sketch up a patch for that...

OK, this turned out a bit more yucky than I assumed, because
SetFileInformationByHandle is only available on Windows Vista and up.
There's a static library (FileExtd.lib) that ships with MSVC that
emulates it for legacy support, I guess I should have a look at what
that does.

-- 
-- 
*** Please reply-to-all at all times ***
*** (do not pretend to know who is subscribed and who is not) ***
*** Please avoid top-posting. ***
The msysGit Wiki is here: https://github.com/msysgit/msysgit/wiki - Github accounts are free.

You received this message because you are subscribed to the Google
Groups "msysGit" group.
To post to this group, send email to msysgit@googlegroups.com
To unsubscribe from this group, send email to
msysgit+unsubscribe@googlegroups.com
For more options, and view previous threads, visit this group at
http://groups.google.com/group/msysgit?hl=en_US?hl=en

--- 
You received this message because you are subscribed to the Google Groups "msysGit" group.
To unsubscribe from this group and stop receiving emails from it, send an email to msysgit+unsubscribe@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

Re: Re: [PATCH v2] config: preserve config file permissions on edits

From: Marius Storm-Olsen <hidden>
Date: 2016-06-15 23:01:14

On 5/19/2014 2:44 AM, Erik Faye-Lund wrote:

On Mon, May 19, 2014 at 9:13 AM, Johannes Sixt [off-list ref]
wrote:

quoted

I'm not proficient enough to add any ACL fiddling to fchmod that
would be required by the above change, whose purpose is to be
strict about permissions. Nor am I interested (who the heck is
sharing a Windows box anyway? ;-)

Since we use MSVCRT's chmod implementation directly which only
checks for S_IWRITE,and Get/SetFileAttributes to simply set or clear
the FILE_ATTRIBUTE_READONLY-flag, perhaps we could do the same
except using Get/SetFileInformationByHandle instead? That takes us in
a better direction, IMO. Adding full ACL support seems like a bigger
project.

If there's no objection, I'll sketch up a patch for that...

IMO, try to stay away from full ACL support, as ACL is slow as hell.
If it's only triggered in edge cases, that's fine, but be sure not to 
add any ACL in the main call-paths as it will surely kill performance.

The major speedup which was done by circumventing MSYS/Cygwin standard 
posix implementations was bypassing much of the ACL slowness.

-- 
.marius

-- 
-- 
*** Please reply-to-all at all times ***
*** (do not pretend to know who is subscribed and who is not) ***
*** Please avoid top-posting. ***
The msysGit Wiki is here: https://github.com/msysgit/msysgit/wiki - Github accounts are free.

You received this message because you are subscribed to the Google
Groups "msysGit" group.
To post to this group, send email to msysgit@googlegroups.com
To unsubscribe from this group, send email to
msysgit+unsubscribe@googlegroups.com
For more options, and view previous threads, visit this group at
http://groups.google.com/group/msysgit?hl=en_US?hl=en

--- 
You received this message because you are subscribed to the Google Groups "msysGit" group.
To unsubscribe from this group and stop receiving emails from it, send an email to msysgit+unsubscribe@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

Re: Re: [PATCH v2] config: preserve config file permissions on edits

From: Thomas Braun <hidden>
Date: 2016-06-15 23:01:15

Am Montag, den 19.05.2014, 11:59 +0200 schrieb Erik Faye-Lund:

On Mon, May 19, 2014 at 9:44 AM, Erik Faye-Lund [off-list ref] wrote:

quoted

On Mon, May 19, 2014 at 9:13 AM, Johannes Sixt [off-list ref] wrote:

quoted

Am 5/6/2014 2:17, schrieb Eric Wong:

quoted

Users may already store sensitive data such as imap.pass in
..git/config; making the file world-readable when "git config"
is called to edit means their password would be compromised
on a shared system.

[v2: updated for section renames, as noted by Junio]

Signed-off-by: Eric Wong <redacted>
---
 config.c               | 16 ++++++++++++++++
 t/t1300-repo-config.sh | 10 ++++++++++
 2 files changed, 26 insertions(+)

diff --git a/config.c b/config.c
index a30cb5c..c227aa8 100644
--- a/config.c
+++ b/config.c

@@ -1636,6 +1636,13 @@ int git_config_set_multivar_in_file(const char *config_filename,
                      MAP_PRIVATE, in_fd, 0);
              close(in_fd);

+             if (fchmod(fd, st.st_mode & 07777) < 0) {
+                     error("fchmod on %s failed: %s",
+                             lock->filename, strerror(errno));
+                     ret = CONFIG_NO_WRITE;
+                     goto out_free;
+             }

This introduces a severe failure in the Windows port because we do not
implement fchmod. Existing fchmod invocations do not check the return
value, and they are only interested in removing the write bits, and we
generally don't care a lot if files remain writable.

I'm not proficient enough to add any ACL fiddling to fchmod that would be
required by the above change, whose purpose is to be strict about
permissions. Nor am I interested (who the heck is sharing a Windows box
anyway? ;-)

Therefore, here's just a work-around patch to keep things going on
Windows. Any opinions from the Windows corner?

Since we use MSVCRT's chmod implementation directly which only checks
for S_IWRITE,and Get/SetFileAttributes to simply set or clear the
FILE_ATTRIBUTE_READONLY-flag, perhaps we could do the same except
using Get/SetFileInformationByHandle instead? That takes us in a
better direction, IMO. Adding full ACL support seems like a bigger
project.

If there's no objection, I'll sketch up a patch for that...

OK, this turned out a bit more yucky than I assumed, because
SetFileInformationByHandle is only available on Windows Vista and up.
There's a static library (FileExtd.lib) that ships with MSVC that
emulates it for legacy support, I guess I should have a look at what
that does.

Do we still want to fully support Windows XP?
Adding a work around here for a EOL operating system sounds like a lot
of effort.



-- 
-- 
*** Please reply-to-all at all times ***
*** (do not pretend to know who is subscribed and who is not) ***
*** Please avoid top-posting. ***
The msysGit Wiki is here: https://github.com/msysgit/msysgit/wiki - Github accounts are free.

You received this message because you are subscribed to the Google
Groups "msysGit" group.
To post to this group, send email to msysgit@googlegroups.com
To unsubscribe from this group, send email to
msysgit+unsubscribe@googlegroups.com
For more options, and view previous threads, visit this group at
http://groups.google.com/group/msysgit?hl=en_US?hl=en

--- 
You received this message because you are subscribed to the Google Groups "msysGit" group.
To unsubscribe from this group and stop receiving emails from it, send an email to msysgit+unsubscribe@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

Re: Re: [PATCH v2] config: preserve config file permissions on edits

From: Erik Faye-Lund <hidden>
Date: 2016-06-15 23:01:15

On Mon, May 19, 2014 at 9:17 PM, Thomas Braun
[off-list ref] wrote:

Am Montag, den 19.05.2014, 11:59 +0200 schrieb Erik Faye-Lund:

quoted

On Mon, May 19, 2014 at 9:44 AM, Erik Faye-Lund [off-list ref] wrote:

quoted

On Mon, May 19, 2014 at 9:13 AM, Johannes Sixt [off-list ref] wrote:

quoted

Am 5/6/2014 2:17, schrieb Eric Wong:

quoted

Users may already store sensitive data such as imap.pass in
..git/config; making the file world-readable when "git config"
is called to edit means their password would be compromised
on a shared system.

[v2: updated for section renames, as noted by Junio]

Signed-off-by: Eric Wong <redacted>
---
 config.c               | 16 ++++++++++++++++
 t/t1300-repo-config.sh | 10 ++++++++++
 2 files changed, 26 insertions(+)

diff --git a/config.c b/config.c
index a30cb5c..c227aa8 100644
--- a/config.c
+++ b/config.c

@@ -1636,6 +1636,13 @@ int git_config_set_multivar_in_file(const char *config_filename,
                      MAP_PRIVATE, in_fd, 0);
              close(in_fd);

+             if (fchmod(fd, st.st_mode & 07777) < 0) {
+                     error("fchmod on %s failed: %s",
+                             lock->filename, strerror(errno));
+                     ret = CONFIG_NO_WRITE;
+                     goto out_free;
+             }

This introduces a severe failure in the Windows port because we do not
implement fchmod. Existing fchmod invocations do not check the return
value, and they are only interested in removing the write bits, and we
generally don't care a lot if files remain writable.

I'm not proficient enough to add any ACL fiddling to fchmod that would be
required by the above change, whose purpose is to be strict about
permissions. Nor am I interested (who the heck is sharing a Windows box
anyway? ;-)

Therefore, here's just a work-around patch to keep things going on
Windows. Any opinions from the Windows corner?

Since we use MSVCRT's chmod implementation directly which only checks
for S_IWRITE,and Get/SetFileAttributes to simply set or clear the
FILE_ATTRIBUTE_READONLY-flag, perhaps we could do the same except
using Get/SetFileInformationByHandle instead? That takes us in a
better direction, IMO. Adding full ACL support seems like a bigger
project.

If there's no objection, I'll sketch up a patch for that...

OK, this turned out a bit more yucky than I assumed, because
SetFileInformationByHandle is only available on Windows Vista and up.
There's a static library (FileExtd.lib) that ships with MSVC that
emulates it for legacy support, I guess I should have a look at what
that does.

Do we still want to fully support Windows XP?
Adding a work around here for a EOL operating system sounds like a lot
of effort.

I personally don't care about Windows XP, but some other influential
people (J6T IIRC) disagreed the last time this was discussed. I don't
want to step on anyone's toes.

-- 
-- 
*** Please reply-to-all at all times ***
*** (do not pretend to know who is subscribed and who is not) ***
*** Please avoid top-posting. ***
The msysGit Wiki is here: https://github.com/msysgit/msysgit/wiki - Github accounts are free.

You received this message because you are subscribed to the Google
Groups "msysGit" group.
To post to this group, send email to msysgit@googlegroups.com
To unsubscribe from this group, send email to
msysgit+unsubscribe@googlegroups.com
For more options, and view previous threads, visit this group at
http://groups.google.com/group/msysgit?hl=en_US?hl=en

--- 
You received this message because you are subscribed to the Google Groups "msysGit" group.
To unsubscribe from this group and stop receiving emails from it, send an email to msysgit+unsubscribe@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

`h`	back out one level
`j`	next message in thread
`k`	previous message in thread
`l`	drill in
`Esc`	close help / fold thread tree
`?`	toggle this help