From: Florian Weimer Date: Fri, 1 Mar 2019 17:53:03 +0000 (+0100) Subject: elf/tst-big-note: Improve accuracy of test [BZ #20419] X-Git-Tag: glibc-2.30~312 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=c259196b5005812aa3294dbf4eeca29b266a4522;p=thirdparty%2Fglibc.git elf/tst-big-note: Improve accuracy of test [BZ #20419] It is possible that the link editor injects an allocated ABI tag note before the artificial, allocated large note in the test. Note parsing in open_verify stops when the first ABI tag note is encountered, so if the ABI tag note comes first, the problematic code is not actually exercised. Also tweak the artificial note so that it is a syntactically valid 4-byte aligned note, in case the link editor tries to parse notes and process them. Improves the testing part of commit 0065aaaaae51cd60210ec3a7e13. Reviewed-by: Carlos O'Donell --- diff --git a/ChangeLog b/ChangeLog index 85506efc998..1ca155ebfc4 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,11 @@ +2019-03-01 Florian Weimer + + [BZ #20419] + * elf/tst-big-note-lib.S: Create a syntactically valid note. + * elf/Makefile (tst-big-note-lib.so): Do not link with startup + code, to avoid creating an ABI tag note. + (modules-names-nobuild): Add tst-big-note-lib. + 2019-03-01 Stefan Liebler * sysdeps/s390/wcscpy-vx.S: Add strong aliases to diff --git a/elf/Makefile b/elf/Makefile index 55204073a31..310a37cc13d 100644 --- a/elf/Makefile +++ b/elf/Makefile @@ -316,8 +316,8 @@ endif modules-execstack-yes = tst-execstack-mod extra-test-objs += $(addsuffix .os,$(strip $(modules-names))) -# filtmod1.so has a special rule -modules-names-nobuild := filtmod1 +# filtmod1.so, tst-big-note-lib.so have special rules. +modules-names-nobuild := filtmod1 tst-big-note-lib tests += $(tests-static) @@ -1515,6 +1515,11 @@ tst-libc_dlvsym-static-ENV = \ $(objpfx)tst-libc_dlvsym-static.out: $(objpfx)tst-libc_dlvsym-dso.so $(objpfx)tst-big-note: $(objpfx)tst-big-note-lib.so +# Avoid creating an ABI tag note, which may come before the +# artificial, large note in tst-big-note-lib.o and invalidate the +# test. +$(objpfx)tst-big-note-lib.so: $(objpfx)tst-big-note-lib.o + $(LINK.o) -shared -o $@ $(LDFLAGS.so) $< $(objpfx)tst-unwind-ctor: $(objpfx)tst-unwind-ctor-lib.so diff --git a/elf/tst-big-note-lib.S b/elf/tst-big-note-lib.S index e2008cf4aee..721686fa0e8 100644 --- a/elf/tst-big-note-lib.S +++ b/elf/tst-big-note-lib.S @@ -20,7 +20,13 @@ On a typical Linux system with 8MiB "ulimit -s", that was enough to trigger stack overflow in open_verify. */ +#define NOTE_SIZE 8*1024*1024 + .pushsection .note.big,"a" -.balign 4 -.fill 8*1024*1024, 1, 0 + .balign 4 + .long 5 /* n_namesz. Length of "GLIBC". */ + .long NOTE_SIZE /* n_descsz. */ + .long 0 /* n_type. */ + .ascii "GLIBC\0\0\0" /* Name and alignment to four bytes. */ + .fill NOTE_SIZE, 1, 0 .popsection