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Eric Biggers
4b90064175
commit0868def3e4upstream. Like the skcipher_walk case: 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 blkcipher_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 blkcipher_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 = "ecb(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:5cde0af2a9("[CRYPTO] cipher: Added block cipher type") Cc: <stable@vger.kernel.org> # v2.6.19+ 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>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.