[PATCH][capabilities-next] commoncap: move assignment of fs_ns to avoid null pointer dereference
From: Colin King <hidden>
Date: 2017-09-04 17:50:09
Also in:
kernel-janitors, lkml
Subsystem:
capabilities, security subsystem, the rest · Maintainers:
Serge Hallyn, Paul Moore, James Morris, Linus Torvalds
From: Colin Ian King <redacted>
The pointer fs_ns is assigned from inode->i_ib->s_user_ns before
a null pointer check on inode, hence if inode is actually null we
will get a null pointer dereference on this assignment. Fix this
by only dereferencing inode after the null pointer check on
inode.
Detected by CoverityScan CID#1455328 ("Dereference before null check")
Fixes: 8db6c34f1dbc ("Introduce v3 namespaced file capabilities")
Signed-off-by: Colin Ian King <redacted>
---
security/commoncap.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/security/commoncap.c b/security/commoncap.c
index c25e0d27537f..fc46f5b85251 100644
--- a/security/commoncap.c
+++ b/security/commoncap.c@@ -585,13 +585,14 @@ int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data struct vfs_ns_cap_data data, *nscaps = &data; struct vfs_cap_data *caps = (struct vfs_cap_data *) &data; kuid_t rootkuid; - struct user_namespace *fs_ns = inode->i_sb->s_user_ns; + struct user_namespace *fs_ns; memset(cpu_caps, 0, sizeof(struct cpu_vfs_cap_data)); if (!inode) return -ENODATA; + fs_ns = inode->i_sb->s_user_ns; size = __vfs_getxattr((struct dentry *)dentry, inode, XATTR_NAME_CAPS, &data, XATTR_CAPS_SZ); if (size == -ENODATA || size == -EOPNOTSUPP)
--
2.14.1
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