crypto: ablkcipher - fix crash flushing dcache in error path

Like the skcipher_walk and blkcipher_walk cases:

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
ablkcipher_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 ablkcipher_walk_done() to skip the
scatterwalk_advance() and scatterwalk_done() if an error has occurred.

Reported-by: Liu Chao <[email protected]>
Fixes: bf06099db18a ("crypto: skcipher - Add ablkcipher_walk interfaces")
Cc: <[email protected]> # v2.6.35+
Signed-off-by: Eric Biggers <[email protected]>
Signed-off-by: Herbert Xu <[email protected]>

0 files changed, 0 insertions, 0 deletions