Date: Mon, 6 Mar 2023 20:56:25 +0300 From: Alexey Izbyshev <izbyshev@...ras.ru> To: musl@...ts.openwall.com Subject: [PATCH] semtimedop: fix timespec kernel ABI mismatch for 32-bit timeouts on x32 For time64 support, musl normally defines SYS_foo to the time32 variant of that syscall on arches that have it, and to the time64 variant otherwise, so that "SYS_foo == SYS_foo_time64" implies that the arch is time64-only. However, SYS_semtimedop is an odd case: some arches define only SYS_semtimedop_time64, yet they are not time64-only, because the time32 variant is provided via SYS_ipc instead. For such arches, defining SYS_semtimedop to SYS_semtimedop_time64 would break the implication above, so commit 4bbd7baea7c8538b3fb8e30f7b022a1eee071450 doesn't do this. Commit eb2e298cdc814493a6ced8c05cf0d0f5cccc8b63 attempts to detect time64-only arches by checking that both SYS_semtimedop and SYS_ipc are undefined, but this doesn't work for x32, because it's a time64-only arch that does define SYS_semtimedop. As a result, 32-bit timeouts trigger the fallback path that passes a 32-bit timespec to the kernel while it expects a 64-bit one, so the effective tv_sec is formed by interpreting 32-bit tv_sec and tv_nsec as a single long long, and the effective tv_nsec is whatever is located in the next 64 bits of the stack. Fix this by expanding the time64-only check to include arches where SYS_semtimedop is the time64 variant of the syscall. --- src/ipc/semtimedop.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/src/ipc/semtimedop.c b/src/ipc/semtimedop.c index 1632e7b0..a104af21 100644 --- a/src/ipc/semtimedop.c +++ b/src/ipc/semtimedop.c @@ -7,7 +7,8 @@ #define IS32BIT(x) !((x)+0x80000000ULL>>32) #define CLAMP(x) (int)(IS32BIT(x) ? (x) : 0x7fffffffU+((0ULL+(x))>>63)) -#if !defined(SYS_semtimedop) && !defined(SYS_ipc) +#if !defined(SYS_semtimedop) && !defined(SYS_ipc) || \ + SYS_semtimedop == SYS_semtimedop_time64 #define NO_TIME32 1 #else #define NO_TIME32 0 -- 2.39.1
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