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author | Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | 2013-02-25 16:20:36 +0100 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-03-12 19:05:45 +0100 |
commit | 8aec0f5d4137532de14e6554fd5dd201ff3a3c49 (patch) | |
tree | 314f28e5ad96423c6983aec9270462d76c0bb343 /security/keys/compat.c | |
parent | Merge branch 'drm-fixes' of git://people.freedesktop.org/~airlied/linux (diff) | |
download | linux-8aec0f5d4137532de14e6554fd5dd201ff3a3c49.tar.xz linux-8aec0f5d4137532de14e6554fd5dd201ff3a3c49.zip |
Fix: compat_rw_copy_check_uvector() misuse in aio, readv, writev, and security keys
Looking at mm/process_vm_access.c:process_vm_rw() and comparing it to
compat_process_vm_rw() shows that the compatibility code requires an
explicit "access_ok()" check before calling
compat_rw_copy_check_uvector(). The same difference seems to appear when
we compare fs/read_write.c:do_readv_writev() to
fs/compat.c:compat_do_readv_writev().
This subtle difference between the compat and non-compat requirements
should probably be debated, as it seems to be error-prone. In fact,
there are two others sites that use this function in the Linux kernel,
and they both seem to get it wrong:
Now shifting our attention to fs/aio.c, we see that aio_setup_iocb()
also ends up calling compat_rw_copy_check_uvector() through
aio_setup_vectored_rw(). Unfortunately, the access_ok() check appears to
be missing. Same situation for
security/keys/compat.c:compat_keyctl_instantiate_key_iov().
I propose that we add the access_ok() check directly into
compat_rw_copy_check_uvector(), so callers don't have to worry about it,
and it therefore makes the compat call code similar to its non-compat
counterpart. Place the access_ok() check in the same location where
copy_from_user() can trigger a -EFAULT error in the non-compat code, so
the ABI behaviors are alike on both compat and non-compat.
While we are here, fix compat_do_readv_writev() so it checks for
compat_rw_copy_check_uvector() negative return values.
And also, fix a memory leak in compat_keyctl_instantiate_key_iov() error
handling.
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'security/keys/compat.c')
-rw-r--r-- | security/keys/compat.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/security/keys/compat.c b/security/keys/compat.c index 1c261763f479..d65fa7fa29ba 100644 --- a/security/keys/compat.c +++ b/security/keys/compat.c @@ -40,12 +40,12 @@ static long compat_keyctl_instantiate_key_iov( ARRAY_SIZE(iovstack), iovstack, &iov); if (ret < 0) - return ret; + goto err; if (ret == 0) goto no_payload_free; ret = keyctl_instantiate_key_common(id, iov, ioc, ret, ringid); - +err: if (iov != iovstack) kfree(iov); return ret; |