forked from luck/tmp_suning_uos_patched
bb29648102
syzbot reported a crash in vmac_final() when multiple threads
concurrently use the same "vmac(aes)" transform through AF_ALG. The bug
is pretty fundamental: the VMAC template doesn't separate per-request
state from per-tfm (per-key) state like the other hash algorithms do,
but rather stores it all in the tfm context. That's wrong.
Also, vmac_final() incorrectly zeroes most of the state including the
derived keys and cached pseudorandom pad. Therefore, only the first
VMAC invocation with a given key calculates the correct digest.
Fix these bugs by splitting the per-tfm state from the per-request state
and using the proper init/update/final sequencing for requests.
Reproducer for the crash:
#include <linux/if_alg.h>
#include <sys/socket.h>
#include <unistd.h>
int main()
{
int fd;
struct sockaddr_alg addr = {
.salg_type = "hash",
.salg_name = "vmac(aes)",
};
char buf[256] = { 0 };
fd = socket(AF_ALG, SOCK_SEQPACKET, 0);
bind(fd, (void *)&addr, sizeof(addr));
setsockopt(fd, SOL_ALG, ALG_SET_KEY, buf, 16);
fork();
fd = accept(fd, NULL, NULL);
for (;;)
write(fd, buf, 256);
}
The immediate cause of the crash is that vmac_ctx_t.partial_size exceeds
VMAC_NHBYTES, causing vmac_final() to memset() a negative length.
Reported-by: syzbot+264bca3a6e8d645550d3@syzkaller.appspotmail.com
Fixes:
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||
|---|---|---|
| .. | ||
| acpi | ||
| asm-generic | ||
| clocksource | ||
| crypto | ||
| drm | ||
| dt-bindings | ||
| keys | ||
| kvm | ||
| linux | ||
| math-emu | ||
| media | ||
| memory | ||
| misc | ||
| net | ||
| pcmcia | ||
| ras | ||
| rdma | ||
| scsi | ||
| soc | ||
| sound | ||
| target | ||
| trace | ||
| uapi | ||
| video | ||
| xen | ||