[RFC PATCH 4/4] ima: define a new ima_sb_post_remount hook
STALE3216d
From: Mimi Zohar <hidden>
Date: 2017-08-16 17:30:47
Also in:
linux-fsdevel
Subsystem:
extended verification module (evm), integrity measurement architecture (ima), security subsystem, the rest · Maintainers:
Mimi Zohar, Roberto Sassu, Dmitry Kasatkin, Paul Moore, James Morris, "Serge E. Hallyn", Linus Torvalds
Compare the previous i_version flag with the remounted i_version flag. Only if there is a change, log change message. Signed-off-by: Mimi Zohar <redacted> --- include/linux/ima.h | 9 +++++++++ security/integrity/ima/ima_main.c | 22 ++++++++++++++++++++-- security/security.c | 1 + 3 files changed, 30 insertions(+), 2 deletions(-)
diff --git a/include/linux/ima.h b/include/linux/ima.h
index 4475cb01149c..bd98221c00d5 100644
--- a/include/linux/ima.h
+++ b/include/linux/ima.h@@ -25,6 +25,9 @@ extern int ima_post_read_file(struct file *file, void *buf, loff_t size, extern void ima_post_path_mknod(struct dentry *dentry); extern void ima_sb_post_new_mount(const struct vfsmount *newmnt, const struct path *path); +extern void ima_sb_post_remount(const struct super_block *sb, + unsigned long prev_sb_flags, + const struct path *path); #ifdef CONFIG_IMA_KEXEC extern void ima_add_kexec_buffer(struct kimage *image);
@@ -70,6 +73,12 @@ static inline void ima_post_path_mknod(struct dentry *dentry) static inline void ima_sb_post_new_mount(const struct vfsmount *newmnt, const struct path *path) { } + +static inline void ima_sb_post_remount(const struct super_block *sb, + unsigned long prev_sb_flags, + const struct path *path) +{ } + #endif /* CONFIG_IMA */ #ifndef CONFIG_IMA_KEXEC
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index a0a685189001..1b180f974e8d 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c@@ -373,8 +373,10 @@ void ima_sb_post_new_mount(const struct vfsmount *newmnt, sb = newmnt ? newmnt->mnt_sb : path->mnt->mnt_sb; - if ((sb->s_flags & MS_I_VERSION) || (sb->s_flags & MS_RDONLY) || - (sb->s_flags & MS_KERNMOUNT)) + if ((sb->s_flags & MS_KERNMOUNT) || (sb->s_flags & MS_RDONLY)) + return; + + if (newmnt && (sb->s_flags & MS_I_VERSION)) return; for (i = 0; i < ARRAY_SIZE(pseudo_fs); i++) {
@@ -394,9 +396,25 @@ void ima_sb_post_new_mount(const struct vfsmount *newmnt, if (newmnt) pr_warn("ima: %s mounted without i_version enabled\n", pathname); + else if (sb->s_flags & MS_I_VERSION) + pr_warn("ima: %s re-mounted with i_version enabled\n", + pathname); + else + pr_warn("ima: %s re-mounted without i_version enabled\n", + pathname); __putname(pathbuf); } +void ima_sb_post_remount(const struct super_block *sb, + unsigned long prev_sb_flags, + const struct path *path) +{ + if ((sb->s_flags & MS_I_VERSION) == (prev_sb_flags & MS_I_VERSION)) + return; /* nothing changed */ + + ima_sb_post_new_mount(NULL, path); +} + /** * ima_read_file - pre-measure/appraise hook decision based on policy * @file: pointer to the file to be measured/appraised/audit
diff --git a/security/security.c b/security/security.c
index 7981ad9019c9..1e2051a52b9f 100644
--- a/security/security.c
+++ b/security/security.c@@ -382,6 +382,7 @@ void security_sb_post_remount(const struct super_block *sb, const struct path *path) { call_void_hook(sb_post_remount, sb, prev_sb_flags, path); + ima_sb_post_remount(sb, prev_sb_flags, path); } int security_sb_kern_mount(struct super_block *sb, int flags, void *data)
--
2.7.4
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