diff options
| author | Keir Fraser <keirf@google.com> | 2025-03-26 11:04:47 +0000 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2025-03-28 19:19:31 +0000 |
| commit | a13bfa4fe0d6949cea14718df2d1fe84c38cd113 (patch) | |
| tree | 7ee1832ece88111fb1275631fa6116e174ac880a | |
| parent | 89f43e1ce6f60d4f44399059595ac47f7a90a393 (diff) | |
arm64: mops: Do not dereference src reg for a set operation
The source register is not used for SET* and reading it can result in
a UBSAN out-of-bounds array access error, specifically when the MOPS
exception is taken from a SET* sequence with XZR (reg 31) as the
source. Architecturally this is the only case where a src/dst/size
field in the ESR can be reported as 31.
Prior to 2de451a329cf662b the code in do_el0_mops() was benign as the
use of pt_regs_read_reg() prevented the out-of-bounds access.
Fixes: 2de451a329cf ("KVM: arm64: Add handler for MOPS exceptions")
Cc: <stable@vger.kernel.org> # 6.12.x
Cc: Kristina Martsenko <kristina.martsenko@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: stable@vger.kernel.org
Reviewed-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Keir Fraser <keirf@google.com>
Reviewed-by: Kristina Martšenko <kristina.martsenko@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20250326110448.3792396-1-keirf@google.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
| -rw-r--r-- | arch/arm64/include/asm/traps.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/arm64/include/asm/traps.h b/arch/arm64/include/asm/traps.h index d780d1bd2eac..82cf1f879c61 100644 --- a/arch/arm64/include/asm/traps.h +++ b/arch/arm64/include/asm/traps.h @@ -109,10 +109,9 @@ static inline void arm64_mops_reset_regs(struct user_pt_regs *regs, unsigned lon int dstreg = ESR_ELx_MOPS_ISS_DESTREG(esr); int srcreg = ESR_ELx_MOPS_ISS_SRCREG(esr); int sizereg = ESR_ELx_MOPS_ISS_SIZEREG(esr); - unsigned long dst, src, size; + unsigned long dst, size; dst = regs->regs[dstreg]; - src = regs->regs[srcreg]; size = regs->regs[sizereg]; /* @@ -129,6 +128,7 @@ static inline void arm64_mops_reset_regs(struct user_pt_regs *regs, unsigned lon } } else { /* CPY* instruction */ + unsigned long src = regs->regs[srcreg]; if (!(option_a ^ wrong_option)) { /* Format is from Option B */ if (regs->pstate & PSR_N_BIT) { |