From: Arnd Bergmann Date: Mon, 22 Mar 2021 16:02:41 +0000 (+0100) Subject: security: commoncap: fix -Wstringop-overread warning X-Git-Tag: v5.10.79~5203 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=f37b9c142e1c1ba475ab000479ba2f86b0be0f00;p=platform%2Fkernel%2Flinux-rpi.git security: commoncap: fix -Wstringop-overread warning commit 82e5d8cc768b0c7b03c551a9ab1f8f3f68d5f83f upstream. gcc-11 introdces a harmless warning for cap_inode_getsecurity: security/commoncap.c: In function ‘cap_inode_getsecurity’: security/commoncap.c:440:33: error: ‘memcpy’ reading 16 bytes from a region of size 0 [-Werror=stringop-overread] 440 | memcpy(&nscap->data, &cap->data, sizeof(__le32) * 2 * VFS_CAP_U32); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The problem here is that tmpbuf is initialized to NULL, so gcc assumes it is not accessible unless it gets set by vfs_getxattr_alloc(). This is a legitimate warning as far as I can tell, but the code is correct since it correctly handles the error when that function fails. Add a separate NULL check to tell gcc about it as well. Signed-off-by: Arnd Bergmann Acked-by: Christian Brauner Signed-off-by: James Morris Cc: Andrey Zhizhikin Signed-off-by: Greg Kroah-Hartman --- diff --git a/security/commoncap.c b/security/commoncap.c index a6c9bb4..28d582e 100644 --- a/security/commoncap.c +++ b/security/commoncap.c @@ -391,7 +391,7 @@ int cap_inode_getsecurity(struct inode *inode, const char *name, void **buffer, &tmpbuf, size, GFP_NOFS); dput(dentry); - if (ret < 0) + if (ret < 0 || !tmpbuf) return ret; fs_ns = inode->i_sb->s_user_ns;