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From: "ppluzhnikov at google dot com" <sourceware-bugzilla@sourceware.org> To: glibc-bugs@sourceware.org Subject: [Bug dynamic-link/16046] New: dl_iterate_phdr should not expose internal stub Date: Mon, 14 Oct 2013 20:34:00 -0000 [thread overview] Message-ID: <bug-16046-131@http.sourceware.org/bugzilla/> (raw) https://sourceware.org/bugzilla/show_bug.cgi?id=16046 Bug ID: 16046 Summary: dl_iterate_phdr should not expose internal stub Product: glibc Version: unspecified Status: NEW Severity: normal Priority: P2 Component: dynamic-link Assignee: unassigned at sourceware dot org Reporter: ppluzhnikov at google dot com Test case: #define _GNU_SOURCE #include <stdio.h> #include <link.h> int callback(struct dl_phdr_info *info, size_t size, void *data) { printf("addr=%p name=%s phdr=%p phnum=%d\n", (void*)info->dlpi_addr, info->dlpi_name, info->dlpi_phdr, info->dlpi_phnum); return 0; } int main() { int status; status = dl_iterate_phdr(callback, NULL); return 0; } Using current git trunk, dynamically linked binary shows: addr=(nil) name= phdr=0x400040 phnum=9 addr=0x7fff2a613000 name=linux-vdso.so.1 phdr=0x7fff29d13040 phnum=4 addr=0x7f73a76d4000 name=./libc.so.6 phdr=0x7f73a76d4040 phnum=10 addr=0x7f73a7a87000 name=./elf/ld.so phdr=0x7f73a7a87040 phnum=7 Statically linked binary: addr=(nil) name= phdr=0x400040 phnum=6 addr=(nil) name= phdr=(nil) phnum=0 addr=0x7ffffd5e1000 name=linux-vdso.so.1 phdr=0x7ffffcce1040 phnum=4 Same with glibc-2.15: addr=(nil) name= phdr=0x400040 phnum=6 What is the second entry? People calling dl_iterate_phdr may legitimately expect only real ELF images to appear. At a minimum, this internal entry should be hidden from dl_iterate_phdr. AFAICT, this was added in commit: commit f91f1c0fb89056995f1c9c6a06c361efdf5139e7 Author: Maciej W. Rozycki <macro@codesourcery.com> Date: Fri Jun 28 16:20:26 2013 +0100 [BZ #15022] Correct global-scope dlopen issues in static executables. This change creates a link map in static executables to serve as the global search list for dlopen. It fixes a problem with the inability to access the global symbol object and a crash on an attempt to map a DSO into the global scope. Some code that has become dead after the addition of this link map is removed too and test cases are provided. -- You are receiving this mail because: You are on the CC list for the bug.
next reply other threads:[~2013-10-14 20:34 UTC|newest] Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top 2013-10-14 20:34 ppluzhnikov at google dot com [this message] 2013-10-14 20:35 ` [Bug dynamic-link/16046] " ppluzhnikov at google dot com 2014-01-31 18:03 ` cvs-commit at gcc dot gnu.org 2014-01-31 18:08 ` macro@linux-mips.org 2014-06-13 9:37 ` fweimer at redhat dot com 2014-06-20 20:55 ` cvs-commit at gcc dot gnu.org 2014-08-10 12:35 ` vapier at gentoo dot org
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