Commit 52564262 authored by Christophe Leroy's avatar Christophe Leroy Committed by Michael Ellerman
Browse files

powerpc/signal32: Fix erroneous SIGSEGV on RT signal return 



Return of user_read_access_begin() is tested the wrong way,
leading to a SIGSEGV when the user address is valid and likely
an Oops when the user address is bad.

Fix the test.

Fixes: 887f3ceb ("powerpc/signal32: Convert do_setcontext[_tm]() to user access block")
Signed-off-by: default avatarChristophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/a29aadc54c93bcbf069a83615fa102ca0f59c3ae.1619185912.git.christophe.leroy@csgroup.eu
parent f9cd5f91

arch/powerpc/kernel/signal_32.c

+2 −2
Original line number Diff line number Diff line
@@ -971,7 +971,7 @@ static int do_setcontext(struct ucontext __user *ucp, struct pt_regs *regs, int 
	sigset_t set;

	struct mcontext __user *mcp;



	if (user_read_access_begin(ucp, sizeof(*ucp)))

	if (!user_read_access_begin(ucp, sizeof(*ucp)))

		return -EFAULT;



	unsafe_get_sigset_t(&set, &ucp->uc_sigmask, failed);
@@ -1009,7 +1009,7 @@ static int do_setcontext_tm(struct ucontext __user *ucp, 
	u32 cmcp;

	u32 tm_cmcp;



	if (user_read_access_begin(ucp, sizeof(*ucp)))

	if (!user_read_access_begin(ucp, sizeof(*ucp)))

		return -EFAULT;



	unsafe_get_sigset_t(&set, &ucp->uc_sigmask, failed);