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| author | Nicholas Piggin <npiggin@gmail.com> | 2022-11-27 22:49:28 +1000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-01-18 11:30:31 +0100 |
| commit | 45012bd3c8281248a014501bb0e655bf6904f065 (patch) | |
| tree | e4fc7ad2fd77551d36850680d4a4b30d19913ff8 /arch/powerpc | |
| parent | 5f8bae1562ea239a6b1c1f674ad70e6583a63c38 (diff) | |
| download | linux-stable-45012bd3c8281248a014501bb0e655bf6904f065.tar.gz linux-stable-45012bd3c8281248a014501bb0e655bf6904f065.tar.bz2 linux-stable-45012bd3c8281248a014501bb0e655bf6904f065.zip | |
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/powerpc')
| -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 0af051a1974e..26a31a3b661e 100644 --- a/arch/powerpc/perf/callchain.c +++ b/arch/powerpc/perf/callchain.c @@ -68,6 +68,7 @@ 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 |