[PATCH] net: check net.core.somaxconn sysctl values

Subsystems: networking [general], the rest

STALE4799d

9 messages, 3 authors, 2013-08-03 · open the first message on its own page

[PATCH] net: check net.core.somaxconn sysctl values

From: Roman Gushchin <hidden>
Date: 2013-07-31 14:03:53

It's possible to assign an invalid value to the net.core.somaxconn
sysctl variable, because there is no checks at all.

The sk_max_ack_backlog field of the sock structure is defined as
unsigned short. Therefore, the backlog argument in inet_listen()
shouldn't exceed USHRT_MAX. The backlog argument in the listen() syscall
is truncated to the somaxconn value. So, the somaxconn value shouldn't
exceed 65535 (USHRT_MAX).
Also, negative values of somaxconn are meaningless.

before:
$ sysctl -w net.core.somaxconn=256
net.core.somaxconn = 256
$ sysctl -w net.core.somaxconn=65536
net.core.somaxconn = 65536
$ sysctl -w net.core.somaxconn=-100
net.core.somaxconn = -100

after:
$ sysctl -w net.core.somaxconn=256
net.core.somaxconn = 256
$ sysctl -w net.core.somaxconn=65536
error: "Invalid argument" setting key "net.core.somaxconn"
$ sysctl -w net.core.somaxconn=-100
error: "Invalid argument" setting key "net.core.somaxconn"

Signed-off-by: Roman Gushchin <redacted>
---
  net/core/sysctl_net_core.c | 6 +++++-
  1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c
index cfdb46a..2ff093b 100644
--- a/net/core/sysctl_net_core.c
+++ b/net/core/sysctl_net_core.c

@@ -20,7 +20,9 @@
  #include <net/sock.h>
  #include <net/net_ratelimit.h>

+static int zero = 0;
  static int one = 1;
+static int ushort_max = USHRT_MAX;

  #ifdef CONFIG_RPS
  static int rps_sock_flow_sysctl(ctl_table *table, int write,

@@ -204,7 +206,9 @@ static struct ctl_table netns_core_table[] = {
  		.data		= &init_net.core.sysctl_somaxconn,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
-		.proc_handler	= proc_dointvec
+		.extra1		= &zero,
+		.extra2		= &ushort_max,
+		.proc_handler	= proc_dointvec_minmax
  	},
  	{ }
  };

-- 
1.8.1.2

Re: [PATCH] net: check net.core.somaxconn sysctl values

From: Eric Dumazet <hidden>
Date: 2013-07-31 14:37:42

On Wed, 2013-07-31 at 17:57 +0400, Roman Gushchin wrote:

It's possible to assign an invalid value to the net.core.somaxconn
sysctl variable, because there is no checks at all.

The sk_max_ack_backlog field of the sock structure is defined as
unsigned short. Therefore, the backlog argument in inet_listen()
shouldn't exceed USHRT_MAX. The backlog argument in the listen() syscall
is truncated to the somaxconn value. So, the somaxconn value shouldn't
exceed 65535 (USHRT_MAX).
Also, negative values of somaxconn are meaningless.

before:
$ sysctl -w net.core.somaxconn=256
net.core.somaxconn = 256
$ sysctl -w net.core.somaxconn=65536
net.core.somaxconn = 65536
$ sysctl -w net.core.somaxconn=-100
net.core.somaxconn = -100

after:
$ sysctl -w net.core.somaxconn=256
net.core.somaxconn = 256
$ sysctl -w net.core.somaxconn=65536
error: "Invalid argument" setting key "net.core.somaxconn"
$ sysctl -w net.core.somaxconn=-100
error: "Invalid argument" setting key "net.core.somaxconn"

Signed-off-by: Roman Gushchin <redacted>
---
  net/core/sysctl_net_core.c | 6 +++++-
  1 file changed, 5 insertions(+), 1 deletion(-)


We had a discussion about this one month ago, as Changli Gao posted a
patch. http://patchwork.ozlabs.org/patch/255460/

So proper credits would be nice ;)

Based on a prior patch from Changli Gao

Reported-by: Changli Gao <redacted>
Suggested-by: Eric Dumazet <edumazet@google.com>

Acked-by: Eric Dumazet <edumazet@google.com>

Re: [PATCH] net: check net.core.somaxconn sysctl values

From: Roman Gushchin <hidden>
Date: 2013-07-31 15:10:48

On 31.07.2013 18:37, Eric Dumazet wrote:

On Wed, 2013-07-31 at 17:57 +0400, Roman Gushchin wrote:

quoted

It's possible to assign an invalid value to the net.core.somaxconn
sysctl variable, because there is no checks at all.

The sk_max_ack_backlog field of the sock structure is defined as
unsigned short. Therefore, the backlog argument in inet_listen()
shouldn't exceed USHRT_MAX. The backlog argument in the listen() syscall
is truncated to the somaxconn value. So, the somaxconn value shouldn't
exceed 65535 (USHRT_MAX).
Also, negative values of somaxconn are meaningless.

before:
$ sysctl -w net.core.somaxconn=256
net.core.somaxconn = 256
$ sysctl -w net.core.somaxconn=65536
net.core.somaxconn = 65536
$ sysctl -w net.core.somaxconn=-100
net.core.somaxconn = -100

after:
$ sysctl -w net.core.somaxconn=256
net.core.somaxconn = 256
$ sysctl -w net.core.somaxconn=65536
error: "Invalid argument" setting key "net.core.somaxconn"
$ sysctl -w net.core.somaxconn=-100
error: "Invalid argument" setting key "net.core.somaxconn"

Signed-off-by: Roman Gushchin <redacted>
---
   net/core/sysctl_net_core.c | 6 +++++-
   1 file changed, 5 insertions(+), 1 deletion(-)


We had a discussion about this one month ago, as Changli Gao posted a
patch. http://patchwork.ozlabs.org/patch/255460/

So proper credits would be nice ;)

Ok :)

Based on a prior patch from Changli Gao

Reported-by: Changli Gao <redacted>
Suggested-by: Eric Dumazet <edumazet@google.com>

Acked-by: Eric Dumazet <edumazet@google.com>

Thanks!

PS I've forwarded your letter back to the lkml by mistake.
Sorry)

Regards,
Roman

Re: [PATCH] net: check net.core.somaxconn sysctl values

From: David Miller <davem@davemloft.net>
Date: 2013-08-01 00:10:22

From: Roman Gushchin <redacted>
Date: Wed, 31 Jul 2013 17:57:35 +0400

quoted hunk

---
 net/core/sysctl_net_core.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c
index cfdb46a..2ff093b 100644
--- a/net/core/sysctl_net_core.c
+++ b/net/core/sysctl_net_core.c

@@ -20,7 +20,9 @@

This patch is against old sources, please respin it against the current
tree.

Thanks.

Re: [PATCH] net: check net.core.somaxconn sysctl values

From: Roman Gushchin <hidden>
Date: 2013-08-01 09:04:29

On 01.08.2013 04:10, David Miller wrote:

From: Roman Gushchin <redacted>
Date: Wed, 31 Jul 2013 17:57:35 +0400

quoted

---
  net/core/sysctl_net_core.c | 6 +++++-
  1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c
index cfdb46a..2ff093b 100644
--- a/net/core/sysctl_net_core.c
+++ b/net/core/sysctl_net_core.c

@@ -20,7 +20,9 @@

This patch is against old sources, please respin it against the current
tree.

Thanks.

net: check net.core.somaxconn sysctl values

It's possible to assign an invalid value to the net.core.somaxconn
sysctl variable, because there is no checks at all.

The sk_max_ack_backlog field of the sock structure is defined as
unsigned short. Therefore, the backlog argument in inet_listen()
shouldn't exceed USHRT_MAX. The backlog argument in the listen() syscall
is truncated to the somaxconn value. So, the somaxconn value shouldn't
exceed 65535 (USHRT_MAX).
Also, negative values of somaxconn are meaningless.

before:
$ sysctl -w net.core.somaxconn=256
net.core.somaxconn = 256
$ sysctl -w net.core.somaxconn=65536
net.core.somaxconn = 65536
$ sysctl -w net.core.somaxconn=-100
net.core.somaxconn = -100

after:
$ sysctl -w net.core.somaxconn=256
net.core.somaxconn = 256
$ sysctl -w net.core.somaxconn=65536
error: "Invalid argument" setting key "net.core.somaxconn"
$ sysctl -w net.core.somaxconn=-100
error: "Invalid argument" setting key "net.core.somaxconn"

Based on a prior patch from Changli Gao.

Signed-off-by: Roman Gushchin <redacted>
Reported-by: Changli Gao <redacted>
Suggested-by: Eric Dumazet <edumazet@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>
---
  net/core/sysctl_net_core.c | 6 +++++-
  1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c
index 6609686..7c37dcd 100644
--- a/net/core/sysctl_net_core.c
+++ b/net/core/sysctl_net_core.c

@@ -21,7 +21,9 @@
  #include <net/net_ratelimit.h>
  #include <net/busy_poll.h>

+static int zero = 0;
  static int one = 1;
+static int ushort_max = USHRT_MAX;

  #ifdef CONFIG_RPS
  static int rps_sock_flow_sysctl(struct ctl_table *table, int write,

@@ -339,7 +341,9 @@ static struct ctl_table netns_core_table[] = {
  		.data		= &init_net.core.sysctl_somaxconn,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
-		.proc_handler	= proc_dointvec
+		.extra1		= &zero,
+		.extra2		= &ushort_max,
+		.proc_handler	= proc_dointvec_minmax
  	},
  	{ }
  };

-- 
1.8.1.2

Re: [PATCH] net: check net.core.somaxconn sysctl values

From: David Miller <davem@davemloft.net>
Date: 2013-08-01 21:18:39

From: Roman Gushchin <redacted>
Date: Thu, 01 Aug 2013 13:04:16 +0400

On 01.08.2013 04:10, David Miller wrote:

quoted

From: Roman Gushchin <redacted>
Date: Wed, 31 Jul 2013 17:57:35 +0400

quoted

---
  net/core/sysctl_net_core.c | 6 +++++-
  1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c
index cfdb46a..2ff093b 100644
--- a/net/core/sysctl_net_core.c
+++ b/net/core/sysctl_net_core.c

@@ -20,7 +20,9 @@

This patch is against old sources, please respin it against the
current
tree.

Thanks.

net: check net.core.somaxconn sysctl values

Still doesn't apply, and it's because your email client has corrupted
the patch.

Please read Documentation/email-clients.txt to learn how to fix this
problem, and then send a test patch to yourself.

Only when you can successfully apply the test patch you send to
yourself should you repost your patch here.

Thanks.

[PATCH] net: check net.core.somaxconn sysctl values

From: Roman Gushchin <hidden>
Date: 2013-08-02 14:37:27

It's possible to assign an invalid value to the net.core.somaxconn
sysctl variable, because there is no checks at all.

The sk_max_ack_backlog field of the sock structure is defined as
unsigned short. Therefore, the backlog argument in inet_listen()
shouldn't exceed USHRT_MAX. The backlog argument in the listen() syscall
is truncated to the somaxconn value. So, the somaxconn value shouldn't
exceed 65535 (USHRT_MAX).
Also, negative values of somaxconn are meaningless.

before:
$ sysctl -w net.core.somaxconn=256
net.core.somaxconn = 256
$ sysctl -w net.core.somaxconn=65536
net.core.somaxconn = 65536
$ sysctl -w net.core.somaxconn=-100
net.core.somaxconn = -100

after:
$ sysctl -w net.core.somaxconn=256
net.core.somaxconn = 256
$ sysctl -w net.core.somaxconn=65536
error: "Invalid argument" setting key "net.core.somaxconn"
$ sysctl -w net.core.somaxconn=-100
error: "Invalid argument" setting key "net.core.somaxconn"

Based on a prior patch from Changli Gao.

Signed-off-by: Roman Gushchin <redacted>
Reported-by: Changli Gao <redacted>
Suggested-by: Eric Dumazet <edumazet@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>
---
 net/core/sysctl_net_core.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c
index 6609686..7c37dcd 100644
--- a/net/core/sysctl_net_core.c
+++ b/net/core/sysctl_net_core.c

@@ -21,7 +21,9 @@
 #include <net/net_ratelimit.h>
 #include <net/busy_poll.h>
 
+static int zero = 0;
 static int one = 1;
+static int ushort_max = USHRT_MAX;
 
 #ifdef CONFIG_RPS
 static int rps_sock_flow_sysctl(struct ctl_table *table, int write,

@@ -339,7 +341,9 @@ static struct ctl_table netns_core_table[] = {
 		.data		= &init_net.core.sysctl_somaxconn,
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec
+		.extra1		= &zero,
+		.extra2		= &ushort_max,
+		.proc_handler	= proc_dointvec_minmax
 	},
 	{ }
 };

-- 
1.8.1.2

Re: [PATCH] net: check net.core.somaxconn sysctl values

From: David Miller <davem@davemloft.net>
Date: 2013-08-02 22:19:17

From: Roman Gushchin <redacted>
Date: Fri,  2 Aug 2013 18:36:40 +0400

It's possible to assign an invalid value to the net.core.somaxconn
sysctl variable, because there is no checks at all.

The sk_max_ack_backlog field of the sock structure is defined as
unsigned short. Therefore, the backlog argument in inet_listen()
shouldn't exceed USHRT_MAX. The backlog argument in the listen() syscall
is truncated to the somaxconn value. So, the somaxconn value shouldn't
exceed 65535 (USHRT_MAX).
Also, negative values of somaxconn are meaningless.

before:
$ sysctl -w net.core.somaxconn=256
net.core.somaxconn = 256
$ sysctl -w net.core.somaxconn=65536
net.core.somaxconn = 65536
$ sysctl -w net.core.somaxconn=-100
net.core.somaxconn = -100

after:
$ sysctl -w net.core.somaxconn=256
net.core.somaxconn = 256
$ sysctl -w net.core.somaxconn=65536
error: "Invalid argument" setting key "net.core.somaxconn"
$ sysctl -w net.core.somaxconn=-100
error: "Invalid argument" setting key "net.core.somaxconn"

Based on a prior patch from Changli Gao.

Signed-off-by: Roman Gushchin <redacted>
Reported-by: Changli Gao <redacted>
Suggested-by: Eric Dumazet <edumazet@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>

Applied, thanks.

Re: [PATCH] net: check net.core.somaxconn sysctl values

From: Roman Gushchin <hidden>
Date: 2013-08-03 10:14:58

On 03.08.2013 02:19, David Miller wrote:

From: Roman Gushchin <redacted>
Date: Fri,  2 Aug 2013 18:36:40 +0400

quoted

It's possible to assign an invalid value to the net.core.somaxconn
sysctl variable, because there is no checks at all.

The sk_max_ack_backlog field of the sock structure is defined as
unsigned short. Therefore, the backlog argument in inet_listen()
shouldn't exceed USHRT_MAX. The backlog argument in the listen() syscall
is truncated to the somaxconn value. So, the somaxconn value shouldn't
exceed 65535 (USHRT_MAX).
Also, negative values of somaxconn are meaningless.

before:
$ sysctl -w net.core.somaxconn=256
net.core.somaxconn = 256
$ sysctl -w net.core.somaxconn=65536
net.core.somaxconn = 65536
$ sysctl -w net.core.somaxconn=-100
net.core.somaxconn = -100

after:
$ sysctl -w net.core.somaxconn=256
net.core.somaxconn = 256
$ sysctl -w net.core.somaxconn=65536
error: "Invalid argument" setting key "net.core.somaxconn"
$ sysctl -w net.core.somaxconn=-100
error: "Invalid argument" setting key "net.core.somaxconn"

Based on a prior patch from Changli Gao.

Signed-off-by: Roman Gushchin <redacted>
Reported-by: Changli Gao <redacted>
Suggested-by: Eric Dumazet <edumazet@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>

Applied, thanks.

Thank you!

Regards,
Roman

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