[PATCH] readelf: PR28928 - wrong dynamic section entry number
Di Chen
dichen@redhat.com
Tue Mar 1 12:54:04 GMT 2022
commit 978663c5323cf402cd35b8614e41f24b587cbdd8 (HEAD -> dichen/DT_NULL,
origin/dichen/DT_NULL)
Author: Di Chen <dichen@redhat.com>
Date: Tue Mar 1 20:44:38 2022 +0800
readelf: PR28928 - wrong dynamic section entry number
when using `$ eu-readelf -d {file}` to get the number of dynamic
section entris, It wrongly counts the padding DT_NULLs as dynamic
section entries. However, DT_NULL Marks end of dynamic section.
They should not be counted as dynamic section entries.
https://sourceware.org/bugzilla/show_bug.cgi?id=28928
Signed-off-by: Di Chen <dichen@redhat.com>
diff --git a/src/readelf.c b/src/readelf.c
index 93fb5989..1bec3aa6 100644
--- a/src/readelf.c
+++ b/src/readelf.c
@@ -296,6 +296,7 @@ static void print_shdr (Ebl *ebl, GElf_Ehdr *ehdr);
static void print_phdr (Ebl *ebl, GElf_Ehdr *ehdr);
static void print_scngrp (Ebl *ebl);
static void print_dynamic (Ebl *ebl);
+static void handle_dynamic (Ebl *ebl, Elf_Scn *scn, GElf_Shdr *shdr);
static void print_relocs (Ebl *ebl, GElf_Ehdr *ehdr);
static void handle_relocs_rel (Ebl *ebl, GElf_Ehdr *ehdr, Elf_Scn *scn,
GElf_Shdr *shdr);
@@ -1781,16 +1782,54 @@ print_dt_posflag_1 (int class, GElf_Xword d_val)
[dichen@arpeggio elfutils]$ git format-patch -1 HEAD
0001-readelf-PR28928-wrong-dynamic-section-entry-number.patch
[dichen@arpeggio elfutils]$ vim
0001-readelf-PR28928-wrong-dynamic-section-entry-number.patch
[dichen@arpeggio elfutils]$ cat
0001-readelf-PR28928-wrong-dynamic-section-entry-number.patch
>From 978663c5323cf402cd35b8614e41f24b587cbdd8 Mon Sep 17 00:00:00 2001
From: Di Chen <dichen@redhat.com>
Date: Tue, 1 Mar 2022 20:44:38 +0800
Subject: [PATCH] readelf: PR28928 - wrong dynamic section entry number
when using `$ eu-readelf -d {file}` to get the number of dynamic
section entris, It wrongly counts the padding DT_NULLs as dynamic
section entries. However, DT_NULL Marks end of dynamic section.
They should not be counted as dynamic section entries.
https://sourceware.org/bugzilla/show_bug.cgi?id=28928
Signed-off-by: Di Chen <dichen@redhat.com>
---
src/readelf.c | 49 ++++++++++++++++++++++++++++++++++++------
tests/alldts.c | 5 +++--
tests/run-alldts.sh | 2 +-
tests/run-readelf-d.sh | 7 +-----
4 files changed, 48 insertions(+), 15 deletions(-)
diff --git a/src/readelf.c b/src/readelf.c
index 93fb5989..1bec3aa6 100644
--- a/src/readelf.c
+++ b/src/readelf.c
@@ -296,6 +296,7 @@ static void print_shdr (Ebl *ebl, GElf_Ehdr *ehdr);
static void print_phdr (Ebl *ebl, GElf_Ehdr *ehdr);
static void print_scngrp (Ebl *ebl);
static void print_dynamic (Ebl *ebl);
+static void handle_dynamic (Ebl *ebl, Elf_Scn *scn, GElf_Shdr *shdr);
static void print_relocs (Ebl *ebl, GElf_Ehdr *ehdr);
static void handle_relocs_rel (Ebl *ebl, GElf_Ehdr *ehdr, Elf_Scn *scn,
GElf_Shdr *shdr);
@@ -1781,16 +1782,54 @@ print_dt_posflag_1 (int class, GElf_Xword d_val)
}
+static GElf_Phdr *
+get_dyn_phdr (Elf *elf)
+{
+ GElf_Phdr *phdr = NULL;
+ for (size_t i = 0; i < phnum; ++i) {
+ GElf_Phdr phdr_mem;
+ phdr = gelf_getphdr(elf, i, &phdr_mem);
+ if (phdr->p_type == PT_DYNAMIC) {
+ break;
+ }
+ }
+ return phdr;
+}
+
+
+static size_t
+get_dyn_scnents (Elf *elf, GElf_Phdr * dyn_phdr)
+{
+ Elf_Data *data = elf_getdata_rawchunk(
+ elf, dyn_phdr->p_offset, dyn_phdr->p_filesz, ELF_T_DYN);
+ GElf_Dyn *dyn;
+ size_t dyn_idx = 0;
+ do
+ {
+ GElf_Dyn dyn_mem;
+ dyn = gelf_getdyn(data, dyn_idx, &dyn_mem);
+ ++dyn_idx;
+ } while (dyn->d_tag != DT_NULL);
+
+ return dyn_idx;
+}
+
+
static void
handle_dynamic (Ebl *ebl, Elf_Scn *scn, GElf_Shdr *shdr)
{
int class = gelf_getclass (ebl->elf);
+ GElf_Phdr *dyn_phdr;
GElf_Shdr glink_mem;
GElf_Shdr *glink;
Elf_Data *data;
size_t cnt;
size_t shstrndx;
- size_t sh_entsize;
+ size_t dyn_scnents;
+
+ /* Calculate the dynamic section entry number */
+ dyn_phdr = get_dyn_phdr (ebl->elf);
+ dyn_scnents = get_dyn_scnents (ebl->elf, dyn_phdr);
/* Get the data of the section. */
data = elf_getdata (scn, NULL);
@@ -1802,8 +1841,6 @@ handle_dynamic (Ebl *ebl, Elf_Scn *scn, GElf_Shdr
*shdr)
error (EXIT_FAILURE, 0,
_("cannot get section header string table index"));
- sh_entsize = gelf_fsize (ebl->elf, ELF_T_DYN, 1, EV_CURRENT);
-
glink = gelf_getshdr (elf_getscn (ebl->elf, shdr->sh_link), &glink_mem);
if (glink == NULL)
error (EXIT_FAILURE, 0, _("invalid sh_link value in section %zu"),
@@ -1813,15 +1850,15 @@ handle_dynamic (Ebl *ebl, Elf_Scn *scn, GElf_Shdr
*shdr)
\nDynamic segment contains %lu entry:\n Addr: %#0*" PRIx64 " Offset:
%#08" PRIx64 " Link to section: [%2u] '%s'\n",
"\
\nDynamic segment contains %lu entries:\n Addr: %#0*" PRIx64 " Offset:
%#08" PRIx64 " Link to section: [%2u] '%s'\n",
- shdr->sh_size / sh_entsize),
- (unsigned long int) (shdr->sh_size / sh_entsize),
+ dyn_scnents),
+ (unsigned long int) dyn_scnents,
class == ELFCLASS32 ? 10 : 18, shdr->sh_addr,
shdr->sh_offset,
(int) shdr->sh_link,
elf_strptr (ebl->elf, shstrndx, glink->sh_name));
fputs_unlocked (_(" Type Value\n"), stdout);
- for (cnt = 0; cnt < shdr->sh_size / sh_entsize; ++cnt)
+ for (cnt = 0; cnt < dyn_scnents; ++cnt)
{
GElf_Dyn dynmem;
GElf_Dyn *dyn = gelf_getdyn (data, cnt, &dynmem);
diff --git a/tests/alldts.c b/tests/alldts.c
index 3e9f9fe6..d0fe4f24 100644
--- a/tests/alldts.c
+++ b/tests/alldts.c
@@ -44,7 +44,7 @@ main (void)
Dwelf_Strent *shstrtabse;
const Elf32_Sword dtflags[] =
{
- DT_NULL, DT_NEEDED, DT_PLTRELSZ, DT_PLTGOT,
+ DT_NEEDED, DT_PLTRELSZ, DT_PLTGOT,
DT_HASH, DT_STRTAB, DT_SYMTAB, DT_RELA,
DT_RELASZ, DT_RELAENT, DT_STRSZ, DT_SYMENT,
DT_INIT, DT_FINI, DT_SONAME, DT_RPATH,
@@ -61,7 +61,8 @@ main (void)
DT_GNU_LIBLIST, DT_CONFIG, DT_DEPAUDIT, DT_AUDIT,
DT_PLTPAD, DT_MOVETAB, DT_SYMINFO, DT_RELACOUNT,
DT_RELCOUNT, DT_FLAGS_1, DT_VERDEF, DT_VERDEFNUM,
- DT_VERNEED, DT_VERNEEDNUM, DT_AUXILIARY, DT_FILTER
+ DT_VERNEED, DT_VERNEEDNUM, DT_AUXILIARY, DT_FILTER,
+ DT_NULL
};
const int ndtflags = sizeof (dtflags) / sizeof (dtflags[0]);
diff --git a/tests/run-alldts.sh b/tests/run-alldts.sh
index 6a9a9ece..bd750a35 100755
--- a/tests/run-alldts.sh
+++ b/tests/run-alldts.sh
@@ -27,7 +27,6 @@ testrun_compare ${abs_top_builddir}/src/readelf -d
testfile-alldts <<\EOF
Dynamic segment contains 66 entries:
Addr: 0x000001a0 Offset: 0x000078 Link to section: [ 0] ''
Type Value
- NULL
NEEDED Shared library: [(null)]
PLTRELSZ 3735928559 (bytes)
PLTGOT 0xdeadbeef
@@ -93,6 +92,7 @@ Dynamic segment contains 66 entries:
VERNEEDNUM 3735928559
AUXILIARY 0xdeadbeef
FILTER 0xdeadbeef
+ NULL
EOF
exit 0
diff --git a/tests/run-readelf-d.sh b/tests/run-readelf-d.sh
index d0b6ed24..69b01c49 100755
--- a/tests/run-readelf-d.sh
+++ b/tests/run-readelf-d.sh
@@ -34,7 +34,7 @@ testfiles testlib_dynseg.so
testrun_compare ${abs_top_builddir}/src/readelf -d testlib_dynseg.so <<\EOF
-Dynamic segment contains 28 entries:
+Dynamic segment contains 23 entries:
Addr: 0x00000000000017e0 Offset: 0x0007e0 Link to section: [ 3]
'.dynstr'
Type Value
PLTGOT 0x00000000000019c8
@@ -60,11 +60,6 @@ Dynamic segment contains 28 entries:
VERNEED 0x0000000000000498
VERNEEDNUM 2
NULL
- NULL
- NULL
- NULL
- NULL
- NULL
EOF
exit 0
--
2.34.1
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