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author | Eric Biggers <ebiggers@google.com> | 2018-07-23 20:54:56 +0300 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-08-17 22:01:10 +0300 |
commit | 7e179bffb6811ecfd653cc651d44bae55941bc97 (patch) | |
tree | db3cddd6d23fe7f9d914bf1e75db987a49ebd927 /.gitignore | |
parent | 0f2981ee03ff3f9678a43592065d0ae95de451dc (diff) | |
download | linux-7e179bffb6811ecfd653cc651d44bae55941bc97.tar.xz |
crypto: skcipher - fix crash flushing dcache in error path
commit 8088d3dd4d7c6933a65aa169393b5d88d8065672 upstream.
scatterwalk_done() is only meant to be called after a nonzero number of
bytes have been processed, since scatterwalk_pagedone() will flush the
dcache of the *previous* page. But in the error case of
skcipher_walk_done(), e.g. if the input wasn't an integer number of
blocks, scatterwalk_done() was actually called after advancing 0 bytes.
This caused a crash ("BUG: unable to handle kernel paging request")
during '!PageSlab(page)' on architectures like arm and arm64 that define
ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE, provided that the input was
page-aligned as in that case walk->offset == 0.
Fix it by reorganizing skcipher_walk_done() to skip the
scatterwalk_advance() and scatterwalk_done() if an error has occurred.
This bug was found by syzkaller fuzzing.
Reproducer, assuming ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE:
#include <linux/if_alg.h>
#include <sys/socket.h>
#include <unistd.h>
int main()
{
struct sockaddr_alg addr = {
.salg_type = "skcipher",
.salg_name = "cbc(aes-generic)",
};
char buffer[4096] __attribute__((aligned(4096))) = { 0 };
int fd;
fd = socket(AF_ALG, SOCK_SEQPACKET, 0);
bind(fd, (void *)&addr, sizeof(addr));
setsockopt(fd, SOL_ALG, ALG_SET_KEY, buffer, 16);
fd = accept(fd, NULL, NULL);
write(fd, buffer, 15);
read(fd, buffer, 15);
}
Reported-by: Liu Chao <liuchao741@huawei.com>
Fixes: b286d8b1a690 ("crypto: skcipher - Add skcipher walk interface")
Cc: <stable@vger.kernel.org> # v4.10+
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to '.gitignore')
0 files changed, 0 insertions, 0 deletions