From: Nicholas Piggin <npiggin@gmail•com>
To: linuxppc-dev@lists•ozlabs.org
Cc: Nicholas Piggin <npiggin@gmail•com>
Subject: [RFC PATCH 01/19] powerpc/perf: callchain validate kernel stack pointer bounds
Date: Mon, 31 Oct 2022 15:54:22 +1000 [thread overview]
Message-ID: <20221031055440.3594315-2-npiggin@gmail.com> (raw)
In-Reply-To: <20221031055440.3594315-1-npiggin@gmail.com>
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.
Signed-off-by: Nicholas Piggin <npiggin@gmail•com>
---
Could the user 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 it could cause a crash at least.
It also seems a bit rude to put a fancy next-frame-validation out in
perf/ rather than with the rest of the frame validation code.
Thanks,
Nick
arch/powerpc/perf/callchain.c | 1 +
1 file changed, 1 insertion(+)
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
--
2.37.2
next prev parent reply other threads:[~2022-10-31 5:55 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-31 5:54 [RFC PATCH 00/19] Remove STACK_FRAME_OVERHEAD Nicholas Piggin
2022-10-31 5:54 ` Nicholas Piggin [this message]
2022-11-04 13:10 ` [RFC PATCH 01/19] powerpc/perf: callchain validate kernel stack pointer bounds Segher Boessenkool
2022-10-31 5:54 ` [RFC PATCH 02/19] powerpc: Rearrange copy_thread child stack creation Nicholas Piggin
2022-10-31 5:54 ` [RFC PATCH 03/19] powerpc/64: Remove asm interrupt tracing call helpers Nicholas Piggin
2022-10-31 5:54 ` [RFC PATCH 04/19] powerpc/pseries: hvcall stack frame overhead Nicholas Piggin
2022-10-31 5:54 ` [RFC PATCH 05/19] powerpc/32: Use load and store multiple in GPR save/restore macros Nicholas Piggin
2022-11-03 8:26 ` Christophe Leroy
2022-11-07 12:45 ` Nicholas Piggin
2022-11-07 12:51 ` Christophe Leroy
2022-10-31 5:54 ` [RFC PATCH 06/19] powerpc: simplify ppc_save_regs Nicholas Piggin
2022-10-31 5:54 ` [RFC PATCH 07/19] powerpc: add definition for pt_regs offset within an interrupt frame Nicholas Piggin
2022-10-31 5:54 ` [RFC PATCH 08/19] powerpc: add a definition for the marker offset within the " Nicholas Piggin
2022-10-31 5:54 ` [RFC PATCH 09/19] powerpc: Rename STACK_FRAME_MARKER and derive it from frame offset Nicholas Piggin
2022-10-31 5:54 ` [RFC PATCH 10/19] powerpc: add a define for the user interrupt frame size Nicholas Piggin
2022-10-31 5:54 ` [RFC PATCH 11/19] powerpc: add a define for the switch frame size and regs offset Nicholas Piggin
2022-10-31 5:54 ` [RFC PATCH 12/19] powerpc: copy_thread fill in interrupt frame marker and back chain Nicholas Piggin
2022-10-31 5:54 ` [RFC PATCH 13/19] powerpc: copy_thread add a back chain to the switch stack frame Nicholas Piggin
2022-10-31 5:54 ` [RFC PATCH 14/19] powerpc: split validate_sp into two functions Nicholas Piggin
2022-11-07 0:58 ` Russell Currey
2022-11-07 12:29 ` Nicholas Piggin
2022-10-31 5:54 ` [RFC PATCH 15/19] powerpc: allow minimum sized kernel stack frames Nicholas Piggin
2022-10-31 5:54 ` [RFC PATCH 16/19] powerpc/64: ELFv2 use minimal stack frames in int and switch frame sizes Nicholas Piggin
2022-10-31 5:54 ` [RFC PATCH 17/19] powerpc: remove STACK_FRAME_OVERHEAD Nicholas Piggin
2022-10-31 5:54 ` [RFC PATCH 18/19] powerpc: change stack marker memory operations to 32-bit Nicholas Piggin
2022-10-31 5:54 ` [RFC PATCH 19/19] powerpc/64: ELFv2 use reserved word in the stack frame for the regs marker Nicholas Piggin
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