Groups > linux.debian.bugs.dist > #1003375

Bug#954294: linux: __X32_SYSCALL_BIT being defined as UL constant breaks userspace (was Re: libseccomp-dev: API break: SCMP_SYS() is unsigned long (was Re: Bug#954294: systemd: FTBFS on x32 due to format string errors, need explicit casts))

From	Thorsten Glaser <t.glaser@tarent.de>
Newsgroups	linux.debian.bugs.dist, linux.debian.kernel
Subject	Bug#954294: linux: __X32_SYSCALL_BIT being defined as UL constant breaks userspace (was Re: libseccomp-dev: API break: SCMP_SYS() is unsigned long (was Re: Bug#954294: systemd: FTBFS on x32 due to format string errors, need explicit casts))
Date	2020-04-07 14:50 +0200
Message-ID	<zSVPY-86M-13@gated-at.bofh.it> (permalink)
References	(3 earlier) <zSCtY-4Ta-21@gated-at.bofh.it> <zSSfo-5UL-3@gated-at.bofh.it> <zSVGi-83p-15@gated-at.bofh.it> <zM9El-8uV-3@gated-at.bofh.it> <zSVGi-83p-15@gated-at.bofh.it>
Organization	linux.* mail to news gateway

Cross-posted to 2 groups.

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Dear kernel team,

libseccomp uses the __NR_* constants from <asm/unistd.h> in its
macro SCMP_SYS() which is designed to return int.

However, on x32 some codes return unsigned long instead, breaking this.
The cause is that this…

> /usr/include/x86_64-linux-gnux32/asm/unistd.h:#define __X32_SYSCALL_BIT 0x40000000UL

… is OR’d into the numbers.

I’d like to propose the change…
-#define __X32_SYSCALL_BIT 0x40000000UL
+#define __X32_SYSCALL_BIT 0x40000000
… which should be safe to do as the number fits into signed int,
but must be checked against other users (especially in the kernel
itself I’d guess).

This should also technically be correct, since on all(?) other
architectures syscall numbers are int constants.

Please forward this to upstream.

Thanks,
//mirabilos
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Thread

Bug#954294: systemd: FTBFS on x32 due to format string errors, need explicit casts Thorsten Glaser <tg@mirbsd.de> - 2020-03-19 21:10 +0100
  Bug#954294: linux: __X32_SYSCALL_BIT being defined as UL constant breaks userspace (was Re: libseccomp-dev: API break: SCMP_SYS() is unsigned long (was Re: Bug#954294: systemd: FTBFS on x32 due to format string errors, need explicit casts)) Thorsten Glaser <t.glaser@tarent.de> - 2020-04-07 14:50 +0200
    Bug#954294: linux: __X32_SYSCALL_BIT being defined as UL constant breaks userspace (was Re: libseccomp-dev: API break: SCMP_SYS() is unsigned long (was Re: Bug#954294: systemd: FTBFS on x32 due to format string errors, need explicit casts)) Ben Hutchings <ben@decadent.org.uk> - 2020-04-08 16:00 +0200
      Bug#954294: linux: __X32_SYSCALL_BIT being defined as UL constant breaks userspace (was Re: libseccomp-dev: API break: SCMP_SYS() is unsigned long (was Re: Bug#954294: systemd: FTBFS on x32 due to format string errors, need explicit casts)) Thorsten Glaser <t.glaser@tarent.de> - 2020-04-08 16:10 +0200
  Bug#954294: libseccomp-dev: API break: SCMP_SYS() is unsigned long (was Re: Bug#954294: systemd: FTBFS on x32 due to format string errors, need explicit casts) Thorsten Glaser <t.glaser@tarent.de> - 2020-04-08 16:10 +0200
  Bug#954294: __X32_SYSCALL_BIT being defined as UL constant breaks userspace Thorsten Glaser <t.glaser@tarent.de> - 2020-04-08 16:30 +0200

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