Re: [PATCH 03/11] security: commoncap: fix -Wstringop-overread warning
On Mon, 22 Mar 2021, Arnd Bergmann wrote: > From: Arnd Bergmann > > 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(>data, >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 Applied to git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security.git fixes-v5.12 -- James Morris
Re: [PATCH 03/11] security: commoncap: fix -Wstringop-overread warning
On Mon, Mar 22, 2021 at 05:02:41PM +0100, Arnd Bergmann wrote: > From: Arnd Bergmann > > 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(>data, >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 > --- Seems reasonable, Acked-by: Christian Brauner
[PATCH 03/11] security: commoncap: fix -Wstringop-overread warning
From: Arnd Bergmann 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(>data, >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 --- security/commoncap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/security/commoncap.c b/security/commoncap.c index 28f4d25480df..9a36ed6dd737 100644 --- a/security/commoncap.c +++ b/security/commoncap.c @@ -400,7 +400,7 @@ int cap_inode_getsecurity(struct user_namespace *mnt_userns, , size, GFP_NOFS); dput(dentry); - if (ret < 0) + if (ret < 0 || !tmpbuf) return ret; fs_ns = inode->i_sb->s_user_ns; -- 2.29.2
