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| author | Eric W. Biederman <ebiederm@xmission.com> | 2017-08-19 23:26:01 +0300 |
|---|---|---|
| committer | Eric W. Biederman <ebiederm@xmission.com> | 2018-01-12 23:21:04 +0300 |
| commit | cf4674c46c66e45f238f8f7e81af2a444b970c0a (patch) | |
| tree | 8742792c826b15a8fe7d673524d3a99415b682b6 /arch/powerpc/include/uapi/asm | |
| parent | b80328be53c215346b153769267b38f531d89b4f (diff) | |
| download | linux-cf4674c46c66e45f238f8f7e81af2a444b970c0a.tar.xz | |
signal/powerpc: Document conflicts with SI_USER and SIGFPE and SIGTRAP
Setting si_code to 0 results in a userspace seeing an si_code of 0.
This is the same si_code as SI_USER. Posix and common sense requires
that SI_USER not be a signal specific si_code. As such this use of 0
for the si_code is a pretty horribly broken ABI.
Further use of si_code == 0 guaranteed that copy_siginfo_to_user saw a
value of __SI_KILL and now sees a value of SIL_KILL with the result
that uid and pid fields are copied and which might copying the si_addr
field by accident but certainly not by design. Making this a very
flakey implementation.
Utilizing FPE_FIXME and TRAP_FIXME, siginfo_layout() will now return
SIL_FAULT and the appropriate fields will be reliably copied.
Possible ABI fixes includee:
- Send the signal without siginfo
- Don't generate a signal
- Possibly assign and use an appropriate si_code
- Don't handle cases which can't happen
Cc: Paul Mackerras <paulus@samba.org>
Cc: Kumar Gala <kumar.gala@freescale.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: linuxppc-dev@lists.ozlabs.org
Ref: 9bad068c24d7 ("[PATCH] ppc32: support for e500 and 85xx")
Ref: 0ed70f6105ef ("PPC32: Provide proper siginfo information on various exceptions.")
History Tree: https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Diffstat (limited to 'arch/powerpc/include/uapi/asm')
| -rw-r--r-- | arch/powerpc/include/uapi/asm/siginfo.h | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/arch/powerpc/include/uapi/asm/siginfo.h b/arch/powerpc/include/uapi/asm/siginfo.h index 1a691141e49f..444ca6c9989a 100644 --- a/arch/powerpc/include/uapi/asm/siginfo.h +++ b/arch/powerpc/include/uapi/asm/siginfo.h @@ -18,4 +18,19 @@ #undef NSIGTRAP #define NSIGTRAP 4 +/* + * SIGFPE si_codes + */ +#ifdef __KERNEL__ +#define FPE_FIXME 0 /* Broken dup of SI_USER */ +#endif /* __KERNEL__ */ + +/* + * SIGTRAP si_codes + */ +#ifdef __KERNEL__ +#define TRAP_FIXME 0 /* Broken dup of SI_USER */ +#endif /* __KERNEL__ */ + + #endif /* _ASM_POWERPC_SIGINFO_H */ |