[ Upstream commit a2f611a3dc317d8ea1c98ad6c54b911cf7f93193 ]
The AFS3 FID is three 32-bit unsigned numbers and is represented as three up-to-8-hex-digit numbers separated by colons to the afs.fid xattr. However, with the advent of support for YFS, the FID is now a 64-bit volume number, a 96-bit vnode/inode number and a 32-bit uniquifier (as before). Whilst the sprintf in afs_xattr_get_fid() has been partially updated (it currently ignores the upper 32 bits of the 96-bit vnode number), the size of the stack-based buffer has not been increased to match, thereby allowing stack corruption to occur.
Fix this by increasing the buffer size appropriately and conditionally including the upper part of the vnode number if it is non-zero. The latter requires the lower part to be zero-padded if the upper part is non-zero.
Fixes: 3b6492df4153 ("afs: Increase to 64-bit volume ID and 96-bit vnode ID for YFS") Signed-off-by: David Howells dhowells@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/afs/xattr.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-)
diff --git a/fs/afs/xattr.c b/fs/afs/xattr.c index a2cdf25573e24..706801c6c4c4c 100644 --- a/fs/afs/xattr.c +++ b/fs/afs/xattr.c @@ -69,11 +69,20 @@ static int afs_xattr_get_fid(const struct xattr_handler *handler, void *buffer, size_t size) { struct afs_vnode *vnode = AFS_FS_I(inode); - char text[8 + 1 + 8 + 1 + 8 + 1]; + char text[16 + 1 + 24 + 1 + 8 + 1]; size_t len;
- len = sprintf(text, "%llx:%llx:%x", - vnode->fid.vid, vnode->fid.vnode, vnode->fid.unique); + /* The volume ID is 64-bit, the vnode ID is 96-bit and the + * uniquifier is 32-bit. + */ + len = sprintf(text, "%llx:", vnode->fid.vid); + if (vnode->fid.vnode_hi) + len += sprintf(text + len, "%x%016llx", + vnode->fid.vnode_hi, vnode->fid.vnode); + else + len += sprintf(text + len, "%llx", vnode->fid.vnode); + len += sprintf(text + len, ":%x", vnode->fid.unique); + if (size == 0) return len; if (len > size)