tmakin/ack-tegra
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

FROMLIST: arm64: mops: Do not dereference src reg for a set operation

Browse Source 
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 2de451a329 the code in do_el0_mops() was benign as the
use of pt_regs_read_reg() prevented the out-of-bounds access.

Fixes: 2de451a329 ("KVM: arm64: Add handler for MOPS exceptions")
Bug: 406015947
Link: https://lore.kernel.org/all/20250326110059.3773318-1-keirf@google.com/
Change-Id: I7e5e195f48b2968310a11fcb314fb7717738bd06
Reviewed-by: Marc Zyngier <maz@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Keir Fraser <keirf@google.com>
This commit is contained in:
Keir Fraser
2025-03-25 14:09:33 +00:00
parent 25e74c53fc
commit 925778f7d1
1 changed files with 2 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files
arch/arm64/include/asm/traps.h
+2 -2
View File
@@ -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) {