From 56062d60f117dccfb5281869e0ab61e090baf864 Mon Sep 17 00:00:00 2001 From: Richard Palethorpe Date: Wed, 10 Jan 2024 15:01:22 +0200 Subject: x86/entry/ia32: Ensure s32 is sign extended to s64 Presently ia32 registers stored in ptregs are unconditionally cast to unsigned int by the ia32 stub. They are then cast to long when passed to __se_sys*, but will not be sign extended. This takes the sign of the syscall argument into account in the ia32 stub. It still casts to unsigned int to avoid implementation specific behavior. However then casts to int or unsigned int as necessary. So that the following cast to long sign extends the value. This fixes the io_pgetevents02 LTP test when compiled with -m32. Presently the systemcall io_pgetevents_time64() unexpectedly accepts -1 for the maximum number of events. It doesn't appear other systemcalls with signed arguments are effected because they all have compat variants defined and wired up. Fixes: ebeb8c82ffaf ("syscalls/x86: Use 'struct pt_regs' based syscall calling for IA32_EMULATION and x32") Suggested-by: Arnd Bergmann Signed-off-by: Richard Palethorpe Signed-off-by: Nikolay Borisov Signed-off-by: Thomas Gleixner Reviewed-by: Arnd Bergmann Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20240110130122.3836513-1-nik.borisov@suse.com Link: https://lore.kernel.org/ltp/20210921130127.24131-1-rpalethorpe@suse.com/ --- include/linux/syscalls.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include') diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index cdba4d0c6d4a..77eb9b0e7685 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -128,6 +128,7 @@ struct mnt_id_req; #define __TYPE_IS_LL(t) (__TYPE_AS(t, 0LL) || __TYPE_AS(t, 0ULL)) #define __SC_LONG(t, a) __typeof(__builtin_choose_expr(__TYPE_IS_LL(t), 0LL, 0L)) a #define __SC_CAST(t, a) (__force t) a +#define __SC_TYPE(t, a) t #define __SC_ARGS(t, a) a #define __SC_TEST(t, a) (void)BUILD_BUG_ON_ZERO(!__TYPE_IS_LL(t) && sizeof(t) > sizeof(long)) -- cgit v1.2.3-58-ga151