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[PATCH 14/17] libdwfl: Don't allocate phdrs and dyn on stack in dwfl_segment_report_module.
- From: Mark Wielaard <mjw at redhat dot com>
- To: elfutils-devel at lists dot fedorahosted dot org
- Date: Sat, 23 May 2015 23:10:27 +0200
- Subject: [PATCH 14/17] libdwfl: Don't allocate phdrs and dyn on stack in dwfl_segment_report_module.
Signed-off-by: Mark Wielaard <mjw@redhat.com>
---
libdwfl/ChangeLog | 6 ++++
libdwfl/dwfl_segment_report_module.c | 67 ++++++++++++++++++++++--------------
2 files changed, 47 insertions(+), 26 deletions(-)
diff --git a/libdwfl/ChangeLog b/libdwfl/ChangeLog
index 8753783..772de3e 100644
--- a/libdwfl/ChangeLog
+++ b/libdwfl/ChangeLog
@@ -1,5 +1,11 @@
2015-05-22 Mark Wielaard <mjw@redhat.com>
+ * dwfl_segment_report_module.c (dwfl_segment_report_module):
+ Allocate phdrs with malloc, not on stack. free in finish.
+ Allocate dyn with malloc, not on stack, free after use.
+
+2015-05-22 Mark Wielaard <mjw@redhat.com>
+
* find-debuginfo.c (find_debuginfo_in_path): malloc or strdup,
instead of alloca or strdupa, local strings of unknown size.
Call free before return.
diff --git a/libdwfl/dwfl_segment_report_module.c b/libdwfl/dwfl_segment_report_module.c
index 898457f..1c3b871 100644
--- a/libdwfl/dwfl_segment_report_module.c
+++ b/libdwfl/dwfl_segment_report_module.c
@@ -1,5 +1,5 @@
/* Sniff out modules from ELF headers visible in memory segments.
- Copyright (C) 2008-2012, 2014 Red Hat, Inc.
+ Copyright (C) 2008-2012, 2014, 2015 Red Hat, Inc.
This file is part of elfutils.
This file is free software; you can redistribute it and/or modify
@@ -36,7 +36,6 @@
#include <gelf.h>
#include <inttypes.h>
#include <sys/param.h>
-#include <alloca.h>
#include <endian.h>
#include <unistd.h>
#include <fcntl.h>
@@ -278,8 +277,13 @@ dwfl_segment_report_module (Dwfl *dwfl, int ndx, const char *name,
Elf *elf = NULL;
int fd = -1;
+ /* We might have to reserve some memory for the phdrs. Set to NULL
+ here so we can always safely free it. */
+ void *phdrsp = NULL;
+
inline int finish (void)
{
+ free (phdrsp);
release_buffer (&buffer, &buffer_available);
if (elf != NULL)
elf_end (elf);
@@ -400,14 +404,19 @@ dwfl_segment_report_module (Dwfl *dwfl, int ndx, const char *name,
xlatefrom.d_buf = ph_buffer;
- union
+ typedef union
{
Elf32_Phdr p32[phnum];
Elf64_Phdr p64[phnum];
- } phdrs;
+ } phdrsn;
- xlateto.d_buf = &phdrs;
- xlateto.d_size = sizeof phdrs;
+ phdrsp = malloc (sizeof (phdrsn));
+ if (phdrsp == NULL)
+ return finish ();
+ phdrsn *phdrs = (phdrsn *) phdrsp;
+
+ xlateto.d_buf = phdrs;
+ xlateto.d_size = sizeof (phdrsn);
/* Track the bounds of the file visible in memory. */
GElf_Off file_trimmed_end = 0; /* Proper p_vaddr + p_filesz end. */
@@ -570,10 +579,10 @@ dwfl_segment_report_module (Dwfl *dwfl, int ndx, const char *name,
found_bias = false; /* Trigger error check. */
else
for (uint_fast16_t i = 0; i < phnum; ++i)
- consider_phdr (phdrs.p32[i].p_type,
- phdrs.p32[i].p_vaddr, phdrs.p32[i].p_memsz,
- phdrs.p32[i].p_offset, phdrs.p32[i].p_filesz,
- phdrs.p32[i].p_align);
+ consider_phdr (phdrs->p32[i].p_type,
+ phdrs->p32[i].p_vaddr, phdrs->p32[i].p_memsz,
+ phdrs->p32[i].p_offset, phdrs->p32[i].p_filesz,
+ phdrs->p32[i].p_align);
}
else
{
@@ -581,10 +590,10 @@ dwfl_segment_report_module (Dwfl *dwfl, int ndx, const char *name,
found_bias = false; /* Trigger error check. */
else
for (uint_fast16_t i = 0; i < phnum; ++i)
- consider_phdr (phdrs.p64[i].p_type,
- phdrs.p64[i].p_vaddr, phdrs.p64[i].p_memsz,
- phdrs.p64[i].p_offset, phdrs.p64[i].p_filesz,
- phdrs.p64[i].p_align);
+ consider_phdr (phdrs->p64[i].p_type,
+ phdrs->p64[i].p_vaddr, phdrs->p64[i].p_memsz,
+ phdrs->p64[i].p_offset, phdrs->p64[i].p_filesz,
+ phdrs->p64[i].p_align);
}
finish_portion (&ph_buffer, &ph_buffer_size);
@@ -735,38 +744,44 @@ dwfl_segment_report_module (Dwfl *dwfl, int ndx, const char *name,
const size_t dyn_entsize = (ei_class == ELFCLASS32
? sizeof (Elf32_Dyn) : sizeof (Elf64_Dyn));
+ void *dyns = NULL;
void *dyn_data = NULL;
size_t dyn_data_size = 0;
if (dyn_filesz != 0 && dyn_filesz % dyn_entsize == 0
&& ! read_portion (&dyn_data, &dyn_data_size, dyn_vaddr, dyn_filesz))
{
- union
+ typedef union
{
Elf32_Dyn d32[dyn_filesz / sizeof (Elf32_Dyn)];
Elf64_Dyn d64[dyn_filesz / sizeof (Elf64_Dyn)];
- } dyn;
+ } dynn;
+ dyns = malloc (sizeof (dynn));
+ if (dyns == NULL)
+ return finish ();
+ dynn *dyn = (dynn *) dyns;
xlatefrom.d_type = xlateto.d_type = ELF_T_DYN;
xlatefrom.d_buf = (void *) dyn_data;
xlatefrom.d_size = dyn_filesz;
- xlateto.d_buf = &dyn;
- xlateto.d_size = sizeof dyn;
+ xlateto.d_buf = dyn;
+ xlateto.d_size = sizeof (dynn);
if (ei_class == ELFCLASS32)
{
if (elf32_xlatetom (&xlateto, &xlatefrom, ei_data) != NULL)
- for (size_t i = 0; i < dyn_filesz / sizeof dyn.d32[0]; ++i)
- if (consider_dyn (dyn.d32[i].d_tag, dyn.d32[i].d_un.d_val))
+ for (size_t i = 0; i < dyn_filesz / sizeof (Elf32_Dyn); ++i)
+ if (consider_dyn (dyn->d32[i].d_tag, dyn->d32[i].d_un.d_val))
break;
}
else
{
if (elf64_xlatetom (&xlateto, &xlatefrom, ei_data) != NULL)
- for (size_t i = 0; i < dyn_filesz / sizeof dyn.d64[0]; ++i)
- if (consider_dyn (dyn.d64[i].d_tag, dyn.d64[i].d_un.d_val))
+ for (size_t i = 0; i < dyn_filesz / sizeof (Elf64_Dyn); ++i)
+ if (consider_dyn (dyn->d64[i].d_tag, dyn->d64[i].d_un.d_val))
break;
}
}
+ free (dyns);
finish_portion (&dyn_data, &dyn_data_size);
/* We'll use the name passed in or a stupid default if not DT_SONAME. */
@@ -881,12 +896,12 @@ dwfl_segment_report_module (Dwfl *dwfl, int ndx, const char *name,
if (ei_class == ELFCLASS32)
for (uint_fast16_t i = 0; i < phnum; ++i)
- read_phdr (phdrs.p32[i].p_type, phdrs.p32[i].p_vaddr,
- phdrs.p32[i].p_offset, phdrs.p32[i].p_filesz);
+ read_phdr (phdrs->p32[i].p_type, phdrs->p32[i].p_vaddr,
+ phdrs->p32[i].p_offset, phdrs->p32[i].p_filesz);
else
for (uint_fast16_t i = 0; i < phnum; ++i)
- read_phdr (phdrs.p64[i].p_type, phdrs.p64[i].p_vaddr,
- phdrs.p64[i].p_offset, phdrs.p64[i].p_filesz);
+ read_phdr (phdrs->p64[i].p_type, phdrs->p64[i].p_vaddr,
+ phdrs->p64[i].p_offset, phdrs->p64[i].p_filesz);
}
else
{
--
1.8.3.1