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Commit a4e7fa8f authored Mar 06, 2023 by Al Viro Committed by Greg Kroah-Hartman Apr 05, 2023

sh: sanitize the flags on sigreturn



[ 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>

parent bcc029c7

arch/sh/include/asm/processor_32.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -57,6 +57,7 @@
		#define SR_FD 0x00008000
		#define SR_MD 0x40000000

		#define SR_USER_MASK 0x00000303 // M, Q, S, T bits
		/*
		* DSP structure and data
		*/

arch/sh/kernel/signal_32.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -116,6 +116,7 @@ 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]);
		@@ -131,6 +132,8 @@ 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;