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authorJosé Bollo <jose.bollo@open.eurogiciel.org>2014-04-03 13:48:41 +0200
committerCasey Schaufler <casey@schaufler-ca.com>2014-04-11 14:35:05 -0700
commit9598f4c9e7069aee8639be1e04e8af26b5a77fa2 (patch)
tree2a23f4d21a289d80e007e674cf6b7e4108404a97 /security/smack
parentbugfix patch for SMACK (diff)
downloadlinux-dev-9598f4c9e7069aee8639be1e04e8af26b5a77fa2.tar.xz
linux-dev-9598f4c9e7069aee8639be1e04e8af26b5a77fa2.zip
SMACK: Fix handling value==NULL in post setxattr
The function `smack_inode_post_setxattr` is called each time that a setxattr is done, for any value of name. The kernel allow to put value==NULL when size==0 to set an empty attribute value. The systematic call to smk_import_entry was causing the dereference of a NULL pointer hence a KERNEL PANIC! The problem can be produced easily by issuing the command `setfattr -n user.data file` under bash prompt when SMACK is active. Moving the call to smk_import_entry as proposed by this patch is correcting the behaviour because the function smack_inode_post_setxattr is called for the SMACK's attributes only if the function smack_inode_setxattr validated the value and its size (what will not be the case when size==0). It also has a benefical effect to not fill the smack hash with garbage values coming from any extended attribute write. Change-Id: Iaf0039c2be9bccb6cee11c24a3b44d209101fe47 Signed-off-by: José Bollo <jose.bollo@open.eurogiciel.org>
Diffstat (limited to 'security/smack')
-rw-r--r--security/smack/smack_lsm.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 9a99f3c485cb..a5d86ffbf9a0 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -960,18 +960,20 @@ static void smack_inode_post_setxattr(struct dentry *dentry, const char *name,
return;
}
- skp = smk_import_entry(value, size);
if (strcmp(name, XATTR_NAME_SMACK) == 0) {
+ skp = smk_import_entry(value, size);
if (skp != NULL)
isp->smk_inode = skp->smk_known;
else
isp->smk_inode = smack_known_invalid.smk_known;
} else if (strcmp(name, XATTR_NAME_SMACKEXEC) == 0) {
+ skp = smk_import_entry(value, size);
if (skp != NULL)
isp->smk_task = skp;
else
isp->smk_task = &smack_known_invalid;
} else if (strcmp(name, XATTR_NAME_SMACKMMAP) == 0) {
+ skp = smk_import_entry(value, size);
if (skp != NULL)
isp->smk_mmap = skp;
else