[PATCH] tools: relocate-rela: Fix ELF decoding on big-endian hosts
Samuel Holland
samuel at sholland.org
Fri Jul 15 08:40:25 CEST 2022
The new ELF decoding logic assumed that the target binary has the same
endianness as the host, which broke building ARM64 firmware binaries on
big-endian machines.
This commit fixes the ELF64 decoding to be host-endianness-neutral, and
applies the same changes to the ELF32 decoding. It does not fix the
microblaze-specific dynamic symbol decoding.
It also corrects the functions used for byte swapping in rela_elf64()
and rela_elf32(). The result is the same, but semantically the code is
converting bytes read from a foreign-endianness file to host byte order.
Fixes: 4c9e2d643460 ("tools: relocate-rela: Read rela start/end directly from ELF")
Fixes: a1405d9cfedb ("tools: relocate-rela: Check that relocation works only for EM_AARCH64")
Signed-off-by: Samuel Holland <samuel at sholland.org>
---
tools/relocate-rela.c | 125 +++++++++++++++++++++++-------------------
1 file changed, 68 insertions(+), 57 deletions(-)
diff --git a/tools/relocate-rela.c b/tools/relocate-rela.c
index 090fb1acb20c..fcf3fb201f07 100644
--- a/tools/relocate-rela.c
+++ b/tools/relocate-rela.c
@@ -60,7 +60,9 @@ static int decode_elf64(FILE *felf, char **argv)
{
size_t size;
Elf64_Ehdr header;
- uint64_t section_header_base, section_header_size, sh_offset, sh_size;
+ uint64_t section_header_base, section_header_size;
+ uint64_t sh_addr, sh_offset, sh_size;
+ Elf64_Half sh_index, sh_num;
Elf64_Shdr *sh_table; /* Elf symbol table */
int ret, i, machine;
char *sh_str;
@@ -76,7 +78,7 @@ static int decode_elf64(FILE *felf, char **argv)
return 25;
}
- machine = header.e_machine;
+ machine = le16_to_cpu(header.e_machine);
debug("Machine\t%d\n", machine);
if (machine != EM_AARCH64) {
@@ -84,9 +86,10 @@ static int decode_elf64(FILE *felf, char **argv)
return 30;
}
- text_base = header.e_entry;
- section_header_base = header.e_shoff;
- section_header_size = header.e_shentsize * header.e_shnum;
+ text_base = le64_to_cpu(header.e_entry);
+ section_header_base = le64_to_cpu(header.e_shoff);
+ section_header_size = le16_to_cpu(header.e_shentsize) *
+ le16_to_cpu(header.e_shnum);
sh_table = malloc(section_header_size);
if (!sh_table) {
@@ -114,9 +117,9 @@ static int decode_elf64(FILE *felf, char **argv)
return 27;
}
- sh_size = sh_table[header.e_shstrndx].sh_size;
- debug("e_shstrndx\t0x%08x\n", header.e_shstrndx);
- debug("sh_size\t\t0x%08lx\n", sh_size);
+ sh_index = le16_to_cpu(header.e_shstrndx);
+ sh_size = le64_to_cpu(sh_table[sh_index].sh_size);
+ debug("e_shstrndx %x, sh_size %lx\n", sh_index, sh_size);
sh_str = malloc(sh_size);
if (!sh_str) {
@@ -130,9 +133,8 @@ static int decode_elf64(FILE *felf, char **argv)
* Specifies the byte offset from the beginning of the file
* to the first byte in the section.
*/
- sh_offset = sh_table[header.e_shstrndx].sh_offset;
-
- debug("sh_offset\t0x%08x\n", header.e_shnum);
+ sh_offset = le64_to_cpu(sh_table[sh_index].sh_offset);
+ sh_num = le16_to_cpu(header.e_shnum);
ret = fseek(felf, sh_offset, SEEK_SET);
if (ret) {
@@ -153,18 +155,22 @@ static int decode_elf64(FILE *felf, char **argv)
return 30;
}
- for (i = 0; i < header.e_shnum; i++) {
- /* fprintf(stderr, "%s\n", sh_str + sh_table[i].sh_name); Debug only */
- if (!strcmp(".rela.dyn", (sh_str + sh_table[i].sh_name))) {
+ for (i = 0; i < sh_num; i++) {
+ char *sh_name = sh_str + le32_to_cpu(sh_table[i].sh_name);
+
+ debug("%s\n", sh_name);
+
+ sh_addr = le64_to_cpu(sh_table[i].sh_addr);
+ sh_offset = le64_to_cpu(sh_table[i].sh_offset);
+ sh_size = le64_to_cpu(sh_table[i].sh_size);
+
+ if (!strcmp(".rela.dyn", sh_name)) {
debug("Found section\t\".rela_dyn\"\n");
- debug(" at addr\t0x%08x\n",
- (unsigned int)sh_table[i].sh_addr);
- debug(" at offset\t0x%08x\n",
- (unsigned int)sh_table[i].sh_offset);
- debug(" of size\t0x%08x\n",
- (unsigned int)sh_table[i].sh_size);
- rela_start = sh_table[i].sh_addr;
- rela_end = rela_start + sh_table[i].sh_size;
+ debug(" at addr\t0x%08x\n", sh_addr);
+ debug(" at offset\t0x%08x\n", sh_offset);
+ debug(" of size\t0x%08x\n", sh_size);
+ rela_start = sh_addr;
+ rela_end = rela_start + sh_size;
break;
}
}
@@ -188,7 +194,9 @@ static int decode_elf32(FILE *felf, char **argv)
{
size_t size;
Elf32_Ehdr header;
- uint64_t section_header_base, section_header_size, sh_offset, sh_size;
+ uint64_t section_header_base, section_header_size;
+ uint32_t sh_addr, sh_offset, sh_size;
+ Elf32_Half sh_index, sh_num;
Elf32_Shdr *sh_table; /* Elf symbol table */
int ret, i, machine;
char *sh_str;
@@ -204,7 +212,7 @@ static int decode_elf32(FILE *felf, char **argv)
return 25;
}
- machine = header.e_machine;
+ machine = le16_to_cpu(header.e_machine);
debug("Machine %d\n", machine);
if (machine != EM_MICROBLAZE) {
@@ -212,14 +220,10 @@ static int decode_elf32(FILE *felf, char **argv)
return 30;
}
- text_base = header.e_entry;
- section_header_base = header.e_shoff;
-
- debug("Section header base %x\n", section_header_base);
-
- section_header_size = header.e_shentsize * header.e_shnum;
-
- debug("Section header size %d\n", section_header_size);
+ text_base = le32_to_cpu(header.e_entry);
+ section_header_base = le32_to_cpu(header.e_shoff);
+ section_header_size = le16_to_cpu(header.e_shentsize) *
+ le16_to_cpu(header.e_shnum);
sh_table = malloc(section_header_size);
if (!sh_table) {
@@ -247,8 +251,9 @@ static int decode_elf32(FILE *felf, char **argv)
return 27;
}
- sh_size = sh_table[header.e_shstrndx].sh_size;
- debug("e_shstrndx %x, sh_size %lx\n", header.e_shstrndx, sh_size);
+ sh_index = le16_to_cpu(header.e_shstrndx);
+ sh_size = le32_to_cpu(sh_table[sh_index].sh_size);
+ debug("e_shstrndx %x, sh_size %lx\n", sh_index, sh_size);
sh_str = malloc(sh_size);
if (!sh_str) {
@@ -262,9 +267,8 @@ static int decode_elf32(FILE *felf, char **argv)
* Specifies the byte offset from the beginning of the file
* to the first byte in the section.
*/
- sh_offset = sh_table[header.e_shstrndx].sh_offset;
-
- debug("sh_offset %x\n", header.e_shnum);
+ sh_offset = le32_to_cpu(sh_table[sh_index].sh_offset);
+ sh_num = le16_to_cpu(header.e_shnum);
ret = fseek(felf, sh_offset, SEEK_SET);
if (ret) {
@@ -277,7 +281,7 @@ static int decode_elf32(FILE *felf, char **argv)
size = fread(sh_str, 1, sh_size, felf);
if (size != sh_size) {
- fprintf(stderr, "%s: Can't read section: %lx/%lx\n",
+ fprintf(stderr, "%s: Can't read section: %lx/%x\n",
argv[0], size, sh_size);
free(sh_str);
free(sh_table);
@@ -285,22 +289,29 @@ static int decode_elf32(FILE *felf, char **argv)
return 30;
}
- for (i = 0; i < header.e_shnum; i++) {
- debug("%s\n", sh_str + sh_table[i].sh_name);
- if (!strcmp(".rela.dyn", (sh_str + sh_table[i].sh_name))) {
+ for (i = 0; i < sh_num; i++) {
+ char *sh_name = sh_str + le32_to_cpu(sh_table[i].sh_name);
+
+ debug("%s\n", sh_name);
+
+ sh_addr = le64_to_cpu(sh_table[i].sh_addr);
+ sh_offset = le64_to_cpu(sh_table[i].sh_offset);
+ sh_size = le64_to_cpu(sh_table[i].sh_size);
+
+ if (!strcmp(".rela.dyn", sh_name)) {
debug("Found section\t\".rela_dyn\"\n");
- debug(" at addr\t0x%08x\n", (unsigned int)sh_table[i].sh_addr);
- debug(" at offset\t0x%08x\n", (unsigned int)sh_table[i].sh_offset);
- debug(" of size\t0x%08x\n", (unsigned int)sh_table[i].sh_size);
- rela_start = sh_table[i].sh_addr;
- rela_end = rela_start + sh_table[i].sh_size;
+ debug(" at addr\t0x%08x\n", sh_addr);
+ debug(" at offset\t0x%08x\n", sh_offset);
+ debug(" of size\t0x%08x\n", sh_size);
+ rela_start = sh_addr;
+ rela_end = rela_start + sh_size;
}
- if (!strcmp(".dynsym", (sh_str + sh_table[i].sh_name))) {
+ if (!strcmp(".dynsym", sh_name)) {
debug("Found section\t\".dynsym\"\n");
- debug(" at addr\t0x%08x\n", (unsigned int)sh_table[i].sh_addr);
- debug(" at offset\t0x%08x\n", (unsigned int)sh_table[i].sh_offset);
- debug(" of size\t0x%08x\n", (unsigned int)sh_table[i].sh_size);
- dyn_start = sh_table[i].sh_addr;
+ debug(" at addr\t0x%08x\n", sh_addr);
+ debug(" at offset\t0x%08x\n", sh_offset);
+ debug(" of size\t0x%08x\n", sh_size);
+ dyn_start = sh_addr;
}
}
@@ -386,9 +397,9 @@ static int rela_elf64(char **argv, FILE *f)
return 4;
}
- swrela.r_offset = cpu_to_le64(rela.r_offset);
- swrela.r_info = cpu_to_le64(rela.r_info);
- swrela.r_addend = cpu_to_le64(rela.r_addend);
+ swrela.r_offset = le64_to_cpu(rela.r_offset);
+ swrela.r_info = le64_to_cpu(rela.r_info);
+ swrela.r_addend = le64_to_cpu(rela.r_addend);
if (!supported_rela(&swrela))
continue;
@@ -487,9 +498,9 @@ static int rela_elf32(char **argv, FILE *f)
PRIu32 " r_addend:\t%" PRIx32 "\n",
rela.r_offset, rela.r_info, rela.r_addend);
- swrela.r_offset = cpu_to_le32(rela.r_offset);
- swrela.r_info = cpu_to_le32(rela.r_info);
- swrela.r_addend = cpu_to_le32(rela.r_addend);
+ swrela.r_offset = le32_to_cpu(rela.r_offset);
+ swrela.r_info = le32_to_cpu(rela.r_info);
+ swrela.r_addend = le32_to_cpu(rela.r_addend);
debug("SWRela:\toffset:\t%" PRIx32 " r_info:\t%"
PRIu32 " r_addend:\t%" PRIx32 "\n",
--
2.35.1
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