diff options
| author | Nicholas Piggin | 2022-11-27 22:49:28 +1000 |
|---|---|---|
| committer | Greg Kroah-Hartman | 2022-12-31 13:32:51 +0100 |
| commit | 5429722209eadaa93e555a012b5f92a4cde34c1f (patch) | |
| tree | e265d285cc143c735bf60eceb3dfd1e7807e6861 /arch | |
| parent | e45e3aae8df8e7fca4c6cfa19eb7afd58a0e64e9 (diff) | |
powerpc/perf: callchain validate kernel stack pointer bounds
[ Upstream commit 32c5209214bd8d4f8c4e9d9b630ef4c671f58e79 ]
The interrupt frame detection and loads from the hypothetical pt_regs
are not bounds-checked. The next-frame validation only bounds-checks
STACK_FRAME_OVERHEAD, which does not include the pt_regs. Add another
test for this.
The user could set r1 to be equal to the address matching the first
interrupt frame - STACK_INT_FRAME_SIZE, which is in the previous page
due to the kernel redzone, and induce the kernel to load the marker from
there. Possibly this could cause a crash at least. If the user could
induce the previous page to contain a valid marker, then it might be
able to direct perf to read specific memory addresses in a way that
could be transmitted back to the user in the perf data.
Fixes: 20002ded4d93 ("perf_counter: powerpc: Add callchain support")
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20221127124942.1665522-4-npiggin@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/powerpc/perf/callchain.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/powerpc/perf/callchain.c b/arch/powerpc/perf/callchain.c index 082f6d0308a4..8718289c051d 100644 --- a/arch/powerpc/perf/callchain.c +++ b/arch/powerpc/perf/callchain.c @@ -61,6 +61,7 @@ perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *re next_sp = fp[0]; if (next_sp == sp + STACK_INT_FRAME_SIZE && + validate_sp(sp, current, STACK_INT_FRAME_SIZE) && fp[STACK_FRAME_MARKER] == STACK_FRAME_REGS_MARKER) { /* * This looks like an interrupt frame for an |