[PATCH v3 08/14] parisc: mask compat syscall arguments in syscall_get_arguments()
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COOLING8d
From: Ricardo Robaina <hidden>
Date: 2026-09-22 19:24:05
Also in:
bpf, linux-alpha, linux-mips, linux-sh, linux-um, lkml, sparclinux
Subsystem:
parisc architecture, the rest · Maintainers:
"James E.J. Bottomley", Helge Deller, Linus Torvalds
Revision v3 of 3 in this series.
Revisions (3)
- v1 [diff vs current]
- v2 [diff vs current]
- v3 current
A 32-bit compat task may leave garbage in the upper 32 bits of the argument registers. Mask it off in syscall_get_arguments() so that in-kernel consumers such as seccomp and audit observe the same values the syscall actually used. This previously happened for audit in the parisc do_syscall_trace_enter() compat path; do it in the helper so all callers benefit and to prepare for passing pt_regs to audit_syscall_entry(). Signed-off-by: Ricardo Robaina <redacted> --- arch/parisc/include/asm/syscall.h | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-)
diff --git a/arch/parisc/include/asm/syscall.h b/arch/parisc/include/asm/syscall.h
index c11222798ab2..9d10fada3b48 100644
--- a/arch/parisc/include/asm/syscall.h
+++ b/arch/parisc/include/asm/syscall.h@@ -28,12 +28,18 @@ static inline void syscall_get_arguments(struct task_struct *tsk, struct pt_regs *regs, unsigned long *args) { - args[5] = regs->gr[21]; - args[4] = regs->gr[22]; - args[3] = regs->gr[23]; - args[2] = regs->gr[24]; - args[1] = regs->gr[25]; - args[0] = regs->gr[26]; + unsigned long mask = -1UL; + + /* Mask off garbage in the upper 32 bits for compat tasks. */ + if (__is_compat_task(tsk)) + mask = 0xffffffff; + + args[5] = regs->gr[21] & mask; + args[4] = regs->gr[22] & mask; + args[3] = regs->gr[23] & mask; + args[2] = regs->gr[24] & mask; + args[1] = regs->gr[25] & mask; + args[0] = regs->gr[26] & mask; } static inline void syscall_set_arguments(struct task_struct *tsk,
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2.55.0