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Always give ELF brands a chance to veto a match.

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If a brand provides a header_supported hook, check it when trying to
find a brand based on a matching interpreter as well as in the final
loop for the fallback brand. Previously a brand might reject a binary
via a header_supported hook in one of the earlier loops, but still be
chosen by one of these later loops.

Reviewed by:	kib
Obtained from:	CheriBSD
MFC after:	2 weeks
Sponsored by:	DARPA / AFRL
Differential Revision:	https://reviews.freebsd.org/D13945
This commit is contained in:
jhb 2018-02-05 23:27:42 +00:00
parent 412ccaa7d2
commit 3f3863ea7c
1 changed files with 6 additions and 3 deletions
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9
sys/kern/imgact_elf.c
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@ -321,7 +321,7 @@ __elfN(get_brandinfo)(struct image_params *imgp, const char *interp,
strcmp((const char *)&hdr->e_ident[OLD_EI_BRAND],
bi->compat_3_brand) == 0))) {
/* Looks good, but give brand a chance to veto */
if (!bi->header_supported ||
if (bi->header_supported == NULL ||
bi->header_supported(imgp)) {
/*
* Again, prefer strictly matching
@ -369,7 +369,8 @@ __elfN(get_brandinfo)(struct image_params *imgp, const char *interp,
/* ELF image p_filesz includes terminating zero */
strlen(bi->interp_path) + 1 == interp_name_len &&
strncmp(interp, bi->interp_path, interp_name_len)
== 0)
== 0 && (bi->header_supported == NULL ||
bi->header_supported(imgp)))
return (bi);
}
}
@ -381,7 +382,9 @@ __elfN(get_brandinfo)(struct image_params *imgp, const char *interp,
(interp != NULL && (bi->flags & BI_BRAND_ONLY_STATIC) != 0))
continue;
if (hdr->e_machine == bi->machine &&
__elfN(fallback_brand) == bi->brand)
__elfN(fallback_brand) == bi->brand &&
(bi->header_supported == NULL ||
bi->header_supported(imgp)))
return (bi);
}
return (NULL);