[PATCH AUTOSEL 6.1 27/29] sh: sanitize the flags on sigreturn
From: Sasha Levin <sashal@kernel.org>
Date: 2023-03-20 00:58:02
Also in:
linux-sh, lkml
Subsystem:
superh, the rest · Maintainers:
Yoshinori Sato, Rich Felker, John Paul Adrian Glaubitz, Linus Torvalds
From: Al Viro <viro@zeniv.linux.org.uk> [ Upstream commit 573b22ccb7ce9ab7f0539a2e11a9d3609a8783f5 ] We fetch %SR value from sigframe; it might have been modified by signal handler, so we can't trust it with any bits that are not modifiable in user mode. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Cc: Rich Felker <dalias@libc.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> --- arch/sh/include/asm/processor_32.h | 1 + arch/sh/kernel/signal_32.c | 3 +++ 2 files changed, 4 insertions(+)
diff --git a/arch/sh/include/asm/processor_32.h b/arch/sh/include/asm/processor_32.h
index 27aebf1e75a20..3ef7adf739c83 100644
--- a/arch/sh/include/asm/processor_32.h
+++ b/arch/sh/include/asm/processor_32.h@@ -50,6 +50,7 @@ #define SR_FD 0x00008000 #define SR_MD 0x40000000 +#define SR_USER_MASK 0x00000303 // M, Q, S, T bits /* * DSP structure and data */
diff --git a/arch/sh/kernel/signal_32.c b/arch/sh/kernel/signal_32.c
index 90f495d35db29..a6bfc6f374911 100644
--- a/arch/sh/kernel/signal_32.c
+++ b/arch/sh/kernel/signal_32.c@@ -115,6 +115,7 @@ static int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, int *r0_p) { unsigned int err = 0; + unsigned int sr = regs->sr & ~SR_USER_MASK; #define COPY(x) err |= __get_user(regs->x, &sc->sc_##x) COPY(regs[1]);
@@ -130,6 +131,8 @@ restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, int *r0_p COPY(sr); COPY(pc); #undef COPY + regs->sr = (regs->sr & SR_USER_MASK) | sr; + #ifdef CONFIG_SH_FPU if (boot_cpu_data.flags & CPU_HAS_FPU) { int owned_fp;
--
2.39.2