* [PATCH] x86/tools/relocs: fix big section header tables
@ 2018-11-29 13:51 Artem Savkov
2018-11-29 14:23 ` Josh Poimboeuf
0 siblings, 1 reply; 8+ messages in thread
From: Artem Savkov @ 2018-11-29 13:51 UTC (permalink / raw)
To: x86; +Cc: Thomas Gleixner, Eric W . Biederman, linux-kernel, Artem Savkov
In case when the number of entries in the section header table is larger
then or equal to SHN_LORESERVE the size of the table is held in the sh_size
member of the initial entry in section header table instead of e_shnum.
Same with the string table index which is located in sh_link instead of
e_shstrndx.
This case is easily reproducible with KCFLAGS="-ffunction-sections",
bzImage build fails with "String table index out of bounds" error.
Signed-off-by: Artem Savkov <asavkov@redhat.com>
---
arch/x86/tools/relocs.c | 58 +++++++++++++++++++++++++++++------------
1 file changed, 41 insertions(+), 17 deletions(-)
diff --git a/arch/x86/tools/relocs.c b/arch/x86/tools/relocs.c
index b629f6992d9f..5275ea0a0d13 100644
--- a/arch/x86/tools/relocs.c
+++ b/arch/x86/tools/relocs.c
@@ -11,7 +11,9 @@
#define Elf_Shdr ElfW(Shdr)
#define Elf_Sym ElfW(Sym)
-static Elf_Ehdr ehdr;
+static Elf_Ehdr ehdr;
+static unsigned long shnum;
+static unsigned int shstrndx;
struct relocs {
uint32_t *offset;
@@ -241,9 +243,9 @@ static const char *sec_name(unsigned shndx)
{
const char *sec_strtab;
const char *name;
- sec_strtab = secs[ehdr.e_shstrndx].strtab;
+ sec_strtab = secs[shstrndx].strtab;
name = "<noname>";
- if (shndx < ehdr.e_shnum) {
+ if (shndx < shnum) {
name = sec_strtab + secs[shndx].shdr.sh_name;
}
else if (shndx == SHN_ABS) {
@@ -271,7 +273,7 @@ static const char *sym_name(const char *sym_strtab, Elf_Sym *sym)
static Elf_Sym *sym_lookup(const char *symname)
{
int i;
- for (i = 0; i < ehdr.e_shnum; i++) {
+ for (i = 0; i < shnum; i++) {
struct section *sec = &secs[i];
long nsyms;
char *strtab;
@@ -366,6 +368,9 @@ static void read_ehdr(FILE *fp)
ehdr.e_shnum = elf_half_to_cpu(ehdr.e_shnum);
ehdr.e_shstrndx = elf_half_to_cpu(ehdr.e_shstrndx);
+ shnum = ehdr.e_shnum;
+ shstrndx = ehdr.e_shstrndx;
+
if ((ehdr.e_type != ET_EXEC) && (ehdr.e_type != ET_DYN)) {
die("Unsupported ELF header type\n");
}
@@ -384,7 +389,26 @@ static void read_ehdr(FILE *fp)
if (ehdr.e_shentsize != sizeof(Elf_Shdr)) {
die("Bad section header entry\n");
}
- if (ehdr.e_shstrndx >= ehdr.e_shnum) {
+
+ if (shnum == SHN_UNDEF || shstrndx == SHN_XINDEX) {
+ Elf_Shdr shdr;
+
+ if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0)
+ die("Seek to %d failed: %s\n",
+ ehdr.e_shoff, strerror(errno));
+
+ if (fread(&shdr, sizeof(shdr), 1, fp) != 1)
+ die("Cannot read initial ELF section header: %s\n",
+ strerror(errno));
+
+ if (shnum == SHN_UNDEF)
+ shnum = elf_xword_to_cpu(shdr.sh_size);
+
+ if (shstrndx == SHN_XINDEX)
+ shstrndx = elf_word_to_cpu(shdr.sh_link);
+ }
+
+ if (shstrndx >= shnum) {
die("String table index out of bounds\n");
}
}
@@ -394,20 +418,20 @@ static void read_shdrs(FILE *fp)
int i;
Elf_Shdr shdr;
- secs = calloc(ehdr.e_shnum, sizeof(struct section));
+ secs = calloc(shnum, sizeof(struct section));
if (!secs) {
die("Unable to allocate %d section headers\n",
- ehdr.e_shnum);
+ shnum);
}
if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0) {
die("Seek to %d failed: %s\n",
ehdr.e_shoff, strerror(errno));
}
- for (i = 0; i < ehdr.e_shnum; i++) {
+ for (i = 0; i < shnum; i++) {
struct section *sec = &secs[i];
if (fread(&shdr, sizeof(shdr), 1, fp) != 1)
die("Cannot read ELF section headers %d/%d: %s\n",
- i, ehdr.e_shnum, strerror(errno));
+ i, shnum, strerror(errno));
sec->shdr.sh_name = elf_word_to_cpu(shdr.sh_name);
sec->shdr.sh_type = elf_word_to_cpu(shdr.sh_type);
sec->shdr.sh_flags = elf_xword_to_cpu(shdr.sh_flags);
@@ -418,7 +442,7 @@ static void read_shdrs(FILE *fp)
sec->shdr.sh_info = elf_word_to_cpu(shdr.sh_info);
sec->shdr.sh_addralign = elf_xword_to_cpu(shdr.sh_addralign);
sec->shdr.sh_entsize = elf_xword_to_cpu(shdr.sh_entsize);
- if (sec->shdr.sh_link < ehdr.e_shnum)
+ if (sec->shdr.sh_link < shnum)
sec->link = &secs[sec->shdr.sh_link];
}
@@ -427,7 +451,7 @@ static void read_shdrs(FILE *fp)
static void read_strtabs(FILE *fp)
{
int i;
- for (i = 0; i < ehdr.e_shnum; i++) {
+ for (i = 0; i < shnum; i++) {
struct section *sec = &secs[i];
if (sec->shdr.sh_type != SHT_STRTAB) {
continue;
@@ -452,7 +476,7 @@ static void read_strtabs(FILE *fp)
static void read_symtabs(FILE *fp)
{
int i,j;
- for (i = 0; i < ehdr.e_shnum; i++) {
+ for (i = 0; i < shnum; i++) {
struct section *sec = &secs[i];
if (sec->shdr.sh_type != SHT_SYMTAB) {
continue;
@@ -485,7 +509,7 @@ static void read_symtabs(FILE *fp)
static void read_relocs(FILE *fp)
{
int i,j;
- for (i = 0; i < ehdr.e_shnum; i++) {
+ for (i = 0; i < shnum; i++) {
struct section *sec = &secs[i];
if (sec->shdr.sh_type != SHT_REL_TYPE) {
continue;
@@ -528,7 +552,7 @@ static void print_absolute_symbols(void)
printf("Absolute symbols\n");
printf(" Num: Value Size Type Bind Visibility Name\n");
- for (i = 0; i < ehdr.e_shnum; i++) {
+ for (i = 0; i < shnum; i++) {
struct section *sec = &secs[i];
char *sym_strtab;
int j;
@@ -566,7 +590,7 @@ static void print_absolute_relocs(void)
else
format = "%08"PRIx32" %08"PRIx32" %10s %08"PRIx32" %s\n";
- for (i = 0; i < ehdr.e_shnum; i++) {
+ for (i = 0; i < shnum; i++) {
struct section *sec = &secs[i];
struct section *sec_applies, *sec_symtab;
char *sym_strtab;
@@ -650,7 +674,7 @@ static void walk_relocs(int (*process)(struct section *sec, Elf_Rel *rel,
{
int i;
/* Walk through the relocations */
- for (i = 0; i < ehdr.e_shnum; i++) {
+ for (i = 0; i < shnum; i++) {
char *sym_strtab;
Elf_Sym *sh_symtab;
struct section *sec_applies, *sec_symtab;
@@ -706,7 +730,7 @@ static Elf_Addr per_cpu_load_addr;
static void percpu_init(void)
{
int i;
- for (i = 0; i < ehdr.e_shnum; i++) {
+ for (i = 0; i < shnum; i++) {
ElfW(Sym) *sym;
if (strcmp(sec_name(i), ".data..percpu"))
continue;
--
2.19.1
^ permalink raw reply related [flat|nested] 8+ messages in thread* Re: [PATCH] x86/tools/relocs: fix big section header tables
2018-11-29 13:51 [PATCH] x86/tools/relocs: fix big section header tables Artem Savkov
@ 2018-11-29 14:23 ` Josh Poimboeuf
2018-11-29 15:22 ` Artem Savkov
0 siblings, 1 reply; 8+ messages in thread
From: Josh Poimboeuf @ 2018-11-29 14:23 UTC (permalink / raw)
To: Artem Savkov; +Cc: x86, Thomas Gleixner, Eric W . Biederman, linux-kernel
On Thu, Nov 29, 2018 at 02:51:33PM +0100, Artem Savkov wrote:
> In case when the number of entries in the section header table is larger
> then or equal to SHN_LORESERVE the size of the table is held in the sh_size
> member of the initial entry in section header table instead of e_shnum.
> Same with the string table index which is located in sh_link instead of
> e_shstrndx.
>
> This case is easily reproducible with KCFLAGS="-ffunction-sections",
> bzImage build fails with "String table index out of bounds" error.
>
> Signed-off-by: Artem Savkov <asavkov@redhat.com>
> ---
> arch/x86/tools/relocs.c | 58 +++++++++++++++++++++++++++++------------
> 1 file changed, 41 insertions(+), 17 deletions(-)
>
> diff --git a/arch/x86/tools/relocs.c b/arch/x86/tools/relocs.c
> index b629f6992d9f..5275ea0a0d13 100644
> --- a/arch/x86/tools/relocs.c
> +++ b/arch/x86/tools/relocs.c
> @@ -11,7 +11,9 @@
> #define Elf_Shdr ElfW(Shdr)
> #define Elf_Sym ElfW(Sym)
>
> -static Elf_Ehdr ehdr;
> +static Elf_Ehdr ehdr;
I think there's a tab missing here, it doesn't line up with the other
variables.
> +static unsigned long shnum;
> +static unsigned int shstrndx;
Otherwise the patch looks good to me.
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
--
Josh
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] x86/tools/relocs: fix big section header tables
2018-11-29 14:23 ` Josh Poimboeuf
@ 2018-11-29 15:22 ` Artem Savkov
2018-11-29 15:32 ` Josh Poimboeuf
0 siblings, 1 reply; 8+ messages in thread
From: Artem Savkov @ 2018-11-29 15:22 UTC (permalink / raw)
To: Josh Poimboeuf; +Cc: x86, Thomas Gleixner, Eric W . Biederman, linux-kernel
On Thu, Nov 29, 2018 at 08:23:12AM -0600, Josh Poimboeuf wrote:
> On Thu, Nov 29, 2018 at 02:51:33PM +0100, Artem Savkov wrote:
> > In case when the number of entries in the section header table is larger
> > then or equal to SHN_LORESERVE the size of the table is held in the sh_size
> > member of the initial entry in section header table instead of e_shnum.
> > Same with the string table index which is located in sh_link instead of
> > e_shstrndx.
> >
> > This case is easily reproducible with KCFLAGS="-ffunction-sections",
> > bzImage build fails with "String table index out of bounds" error.
> >
> > Signed-off-by: Artem Savkov <asavkov@redhat.com>
> > ---
> > arch/x86/tools/relocs.c | 58 +++++++++++++++++++++++++++++------------
> > 1 file changed, 41 insertions(+), 17 deletions(-)
> >
> > diff --git a/arch/x86/tools/relocs.c b/arch/x86/tools/relocs.c
> > index b629f6992d9f..5275ea0a0d13 100644
> > --- a/arch/x86/tools/relocs.c
> > +++ b/arch/x86/tools/relocs.c
> > @@ -11,7 +11,9 @@
> > #define Elf_Shdr ElfW(Shdr)
> > #define Elf_Sym ElfW(Sym)
> >
> > -static Elf_Ehdr ehdr;
> > +static Elf_Ehdr ehdr;
>
> I think there's a tab missing here, it doesn't line up with the other
> variables.
This seems to be a vim bug. It aligns perfectly in
cat/less/lore.kernel.org which all seem to use tabstop=8 by default, but
it does not align in vim, but it does align with tabstop=7 in vim.
--
Artem
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] x86/tools/relocs: fix big section header tables
2018-11-29 15:22 ` Artem Savkov
@ 2018-11-29 15:32 ` Josh Poimboeuf
2018-11-29 15:56 ` [PATCH v2] " Artem Savkov
0 siblings, 1 reply; 8+ messages in thread
From: Josh Poimboeuf @ 2018-11-29 15:32 UTC (permalink / raw)
To: Artem Savkov; +Cc: x86, Thomas Gleixner, Eric W . Biederman, linux-kernel
On Thu, Nov 29, 2018 at 04:22:00PM +0100, Artem Savkov wrote:
> On Thu, Nov 29, 2018 at 08:23:12AM -0600, Josh Poimboeuf wrote:
> > On Thu, Nov 29, 2018 at 02:51:33PM +0100, Artem Savkov wrote:
> > > In case when the number of entries in the section header table is larger
> > > then or equal to SHN_LORESERVE the size of the table is held in the sh_size
> > > member of the initial entry in section header table instead of e_shnum.
> > > Same with the string table index which is located in sh_link instead of
> > > e_shstrndx.
> > >
> > > This case is easily reproducible with KCFLAGS="-ffunction-sections",
> > > bzImage build fails with "String table index out of bounds" error.
> > >
> > > Signed-off-by: Artem Savkov <asavkov@redhat.com>
> > > ---
> > > arch/x86/tools/relocs.c | 58 +++++++++++++++++++++++++++++------------
> > > 1 file changed, 41 insertions(+), 17 deletions(-)
> > >
> > > diff --git a/arch/x86/tools/relocs.c b/arch/x86/tools/relocs.c
> > > index b629f6992d9f..5275ea0a0d13 100644
> > > --- a/arch/x86/tools/relocs.c
> > > +++ b/arch/x86/tools/relocs.c
> > > @@ -11,7 +11,9 @@
> > > #define Elf_Shdr ElfW(Shdr)
> > > #define Elf_Sym ElfW(Sym)
> > >
> > > -static Elf_Ehdr ehdr;
> > > +static Elf_Ehdr ehdr;
> >
> > I think there's a tab missing here, it doesn't line up with the other
> > variables.
>
> This seems to be a vim bug. It aligns perfectly in
> cat/less/lore.kernel.org which all seem to use tabstop=8 by default, but
> it does not align in vim, but it does align with tabstop=7 in vim.
Are you looking at the patch? Or the file itself?
"less arch/x86/tools/relocs.c" shows the same issue.
--
Josh
^ permalink raw reply [flat|nested] 8+ messages in thread
* [PATCH v2] x86/tools/relocs: fix big section header tables
2018-11-29 15:32 ` Josh Poimboeuf
@ 2018-11-29 15:56 ` Artem Savkov
2018-11-29 15:57 ` Josh Poimboeuf
2019-04-19 19:01 ` [tip:x86/build] x86/tools/relocs: Fix " tip-bot for Artem Savkov
0 siblings, 2 replies; 8+ messages in thread
From: Artem Savkov @ 2018-11-29 15:56 UTC (permalink / raw)
To: x86
Cc: Thomas Gleixner, Eric W . Biederman, linux-kernel,
Josh Poimboeuf, Artem Savkov
In case when the number of entries in the section header table is larger
then or equal to SHN_LORESERVE the size of the table is held in the sh_size
member of the initial entry in section header table instead of e_shnum.
Same with the string table index which is located in sh_link instead of
e_shstrndx.
This case is easily reproducible with KCFLAGS="-ffunction-sections",
bzImage build fails with "String table index out of bounds" error.
Signed-off-by: Artem Savkov <asavkov@redhat.com>
---
arch/x86/tools/relocs.c | 58 +++++++++++++++++++++++++++++------------
1 file changed, 41 insertions(+), 17 deletions(-)
diff --git a/arch/x86/tools/relocs.c b/arch/x86/tools/relocs.c
index b629f6992d9f..1f5dcec15d4e 100644
--- a/arch/x86/tools/relocs.c
+++ b/arch/x86/tools/relocs.c
@@ -11,7 +11,9 @@
#define Elf_Shdr ElfW(Shdr)
#define Elf_Sym ElfW(Sym)
-static Elf_Ehdr ehdr;
+static Elf_Ehdr ehdr;
+static unsigned long shnum;
+static unsigned int shstrndx;
struct relocs {
uint32_t *offset;
@@ -241,9 +243,9 @@ static const char *sec_name(unsigned shndx)
{
const char *sec_strtab;
const char *name;
- sec_strtab = secs[ehdr.e_shstrndx].strtab;
+ sec_strtab = secs[shstrndx].strtab;
name = "<noname>";
- if (shndx < ehdr.e_shnum) {
+ if (shndx < shnum) {
name = sec_strtab + secs[shndx].shdr.sh_name;
}
else if (shndx == SHN_ABS) {
@@ -271,7 +273,7 @@ static const char *sym_name(const char *sym_strtab, Elf_Sym *sym)
static Elf_Sym *sym_lookup(const char *symname)
{
int i;
- for (i = 0; i < ehdr.e_shnum; i++) {
+ for (i = 0; i < shnum; i++) {
struct section *sec = &secs[i];
long nsyms;
char *strtab;
@@ -366,6 +368,9 @@ static void read_ehdr(FILE *fp)
ehdr.e_shnum = elf_half_to_cpu(ehdr.e_shnum);
ehdr.e_shstrndx = elf_half_to_cpu(ehdr.e_shstrndx);
+ shnum = ehdr.e_shnum;
+ shstrndx = ehdr.e_shstrndx;
+
if ((ehdr.e_type != ET_EXEC) && (ehdr.e_type != ET_DYN)) {
die("Unsupported ELF header type\n");
}
@@ -384,7 +389,26 @@ static void read_ehdr(FILE *fp)
if (ehdr.e_shentsize != sizeof(Elf_Shdr)) {
die("Bad section header entry\n");
}
- if (ehdr.e_shstrndx >= ehdr.e_shnum) {
+
+ if (shnum == SHN_UNDEF || shstrndx == SHN_XINDEX) {
+ Elf_Shdr shdr;
+
+ if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0)
+ die("Seek to %d failed: %s\n",
+ ehdr.e_shoff, strerror(errno));
+
+ if (fread(&shdr, sizeof(shdr), 1, fp) != 1)
+ die("Cannot read initial ELF section header: %s\n",
+ strerror(errno));
+
+ if (shnum == SHN_UNDEF)
+ shnum = elf_xword_to_cpu(shdr.sh_size);
+
+ if (shstrndx == SHN_XINDEX)
+ shstrndx = elf_word_to_cpu(shdr.sh_link);
+ }
+
+ if (shstrndx >= shnum) {
die("String table index out of bounds\n");
}
}
@@ -394,20 +418,20 @@ static void read_shdrs(FILE *fp)
int i;
Elf_Shdr shdr;
- secs = calloc(ehdr.e_shnum, sizeof(struct section));
+ secs = calloc(shnum, sizeof(struct section));
if (!secs) {
die("Unable to allocate %d section headers\n",
- ehdr.e_shnum);
+ shnum);
}
if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0) {
die("Seek to %d failed: %s\n",
ehdr.e_shoff, strerror(errno));
}
- for (i = 0; i < ehdr.e_shnum; i++) {
+ for (i = 0; i < shnum; i++) {
struct section *sec = &secs[i];
if (fread(&shdr, sizeof(shdr), 1, fp) != 1)
die("Cannot read ELF section headers %d/%d: %s\n",
- i, ehdr.e_shnum, strerror(errno));
+ i, shnum, strerror(errno));
sec->shdr.sh_name = elf_word_to_cpu(shdr.sh_name);
sec->shdr.sh_type = elf_word_to_cpu(shdr.sh_type);
sec->shdr.sh_flags = elf_xword_to_cpu(shdr.sh_flags);
@@ -418,7 +442,7 @@ static void read_shdrs(FILE *fp)
sec->shdr.sh_info = elf_word_to_cpu(shdr.sh_info);
sec->shdr.sh_addralign = elf_xword_to_cpu(shdr.sh_addralign);
sec->shdr.sh_entsize = elf_xword_to_cpu(shdr.sh_entsize);
- if (sec->shdr.sh_link < ehdr.e_shnum)
+ if (sec->shdr.sh_link < shnum)
sec->link = &secs[sec->shdr.sh_link];
}
@@ -427,7 +451,7 @@ static void read_shdrs(FILE *fp)
static void read_strtabs(FILE *fp)
{
int i;
- for (i = 0; i < ehdr.e_shnum; i++) {
+ for (i = 0; i < shnum; i++) {
struct section *sec = &secs[i];
if (sec->shdr.sh_type != SHT_STRTAB) {
continue;
@@ -452,7 +476,7 @@ static void read_strtabs(FILE *fp)
static void read_symtabs(FILE *fp)
{
int i,j;
- for (i = 0; i < ehdr.e_shnum; i++) {
+ for (i = 0; i < shnum; i++) {
struct section *sec = &secs[i];
if (sec->shdr.sh_type != SHT_SYMTAB) {
continue;
@@ -485,7 +509,7 @@ static void read_symtabs(FILE *fp)
static void read_relocs(FILE *fp)
{
int i,j;
- for (i = 0; i < ehdr.e_shnum; i++) {
+ for (i = 0; i < shnum; i++) {
struct section *sec = &secs[i];
if (sec->shdr.sh_type != SHT_REL_TYPE) {
continue;
@@ -528,7 +552,7 @@ static void print_absolute_symbols(void)
printf("Absolute symbols\n");
printf(" Num: Value Size Type Bind Visibility Name\n");
- for (i = 0; i < ehdr.e_shnum; i++) {
+ for (i = 0; i < shnum; i++) {
struct section *sec = &secs[i];
char *sym_strtab;
int j;
@@ -566,7 +590,7 @@ static void print_absolute_relocs(void)
else
format = "%08"PRIx32" %08"PRIx32" %10s %08"PRIx32" %s\n";
- for (i = 0; i < ehdr.e_shnum; i++) {
+ for (i = 0; i < shnum; i++) {
struct section *sec = &secs[i];
struct section *sec_applies, *sec_symtab;
char *sym_strtab;
@@ -650,7 +674,7 @@ static void walk_relocs(int (*process)(struct section *sec, Elf_Rel *rel,
{
int i;
/* Walk through the relocations */
- for (i = 0; i < ehdr.e_shnum; i++) {
+ for (i = 0; i < shnum; i++) {
char *sym_strtab;
Elf_Sym *sh_symtab;
struct section *sec_applies, *sec_symtab;
@@ -706,7 +730,7 @@ static Elf_Addr per_cpu_load_addr;
static void percpu_init(void)
{
int i;
- for (i = 0; i < ehdr.e_shnum; i++) {
+ for (i = 0; i < shnum; i++) {
ElfW(Sym) *sym;
if (strcmp(sec_name(i), ".data..percpu"))
continue;
--
2.19.1
^ permalink raw reply related [flat|nested] 8+ messages in thread* Re: [PATCH v2] x86/tools/relocs: fix big section header tables
2018-11-29 15:56 ` [PATCH v2] " Artem Savkov
@ 2018-11-29 15:57 ` Josh Poimboeuf
2019-01-11 19:09 ` Joe Lawrence
2019-04-19 19:01 ` [tip:x86/build] x86/tools/relocs: Fix " tip-bot for Artem Savkov
1 sibling, 1 reply; 8+ messages in thread
From: Josh Poimboeuf @ 2018-11-29 15:57 UTC (permalink / raw)
To: Artem Savkov; +Cc: x86, Thomas Gleixner, Eric W . Biederman, linux-kernel
On Thu, Nov 29, 2018 at 04:56:15PM +0100, Artem Savkov wrote:
> In case when the number of entries in the section header table is larger
> then or equal to SHN_LORESERVE the size of the table is held in the sh_size
> member of the initial entry in section header table instead of e_shnum.
> Same with the string table index which is located in sh_link instead of
> e_shstrndx.
>
> This case is easily reproducible with KCFLAGS="-ffunction-sections",
> bzImage build fails with "String table index out of bounds" error.
>
> Signed-off-by: Artem Savkov <asavkov@redhat.com>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
--
Josh
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v2] x86/tools/relocs: fix big section header tables
2018-11-29 15:57 ` Josh Poimboeuf
@ 2019-01-11 19:09 ` Joe Lawrence
0 siblings, 0 replies; 8+ messages in thread
From: Joe Lawrence @ 2019-01-11 19:09 UTC (permalink / raw)
To: Josh Poimboeuf
Cc: Artem Savkov, x86, Thomas Gleixner, Eric W . Biederman,
linux-kernel, Ingo Molnar
On Thu, Nov 29, 2018 at 09:57:50AM -0600, Josh Poimboeuf wrote:
> On Thu, Nov 29, 2018 at 04:56:15PM +0100, Artem Savkov wrote:
> > In case when the number of entries in the section header table is larger
> > then or equal to SHN_LORESERVE the size of the table is held in the sh_size
> > member of the initial entry in section header table instead of e_shnum.
> > Same with the string table index which is located in sh_link instead of
> > e_shstrndx.
> >
> > This case is easily reproducible with KCFLAGS="-ffunction-sections",
> > bzImage build fails with "String table index out of bounds" error.
> >
> > Signed-off-by: Artem Savkov <asavkov@redhat.com>
>
> Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
>
Gentle ping to nudge this patch along (I didn't see it in anyone's tree).
Thanks,
--- Joe
^ permalink raw reply [flat|nested] 8+ messages in thread
* [tip:x86/build] x86/tools/relocs: Fix big section header tables
2018-11-29 15:56 ` [PATCH v2] " Artem Savkov
2018-11-29 15:57 ` Josh Poimboeuf
@ 2019-04-19 19:01 ` tip-bot for Artem Savkov
1 sibling, 0 replies; 8+ messages in thread
From: tip-bot for Artem Savkov @ 2019-04-19 19:01 UTC (permalink / raw)
To: linux-tip-commits
Cc: torvalds, ebiederm, hpa, jpoimboe, linux-kernel, asavkov, tglx,
peterz, mingo, joe.lawrence
Commit-ID: f36e7495dd3990d6848e6d6703c78f1f17a97538
Gitweb: https://git.kernel.org/tip/f36e7495dd3990d6848e6d6703c78f1f17a97538
Author: Artem Savkov <asavkov@redhat.com>
AuthorDate: Thu, 29 Nov 2018 16:56:15 +0100
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Fri, 19 Apr 2019 20:54:07 +0200
x86/tools/relocs: Fix big section header tables
In case when the number of entries in the section header table is larger
then or equal to SHN_LORESERVE the size of the table is held in the sh_size
member of the initial entry in section header table instead of e_shnum.
Same with the string table index which is located in sh_link instead of
e_shstrndx.
This case is easily reproducible with KCFLAGS="-ffunction-sections",
bzImage build fails with "String table index out of bounds" error.
Signed-off-by: Artem Savkov <asavkov@redhat.com>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
Cc: Eric W . Biederman <ebiederm@xmission.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20181129155615.2594-1-asavkov@redhat.com
[ Simplify the die() lines. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/tools/relocs.c | 74 ++++++++++++++++++++++++++++++-------------------
1 file changed, 45 insertions(+), 29 deletions(-)
diff --git a/arch/x86/tools/relocs.c b/arch/x86/tools/relocs.c
index b629f6992d9f..f345586f5e50 100644
--- a/arch/x86/tools/relocs.c
+++ b/arch/x86/tools/relocs.c
@@ -11,7 +11,9 @@
#define Elf_Shdr ElfW(Shdr)
#define Elf_Sym ElfW(Sym)
-static Elf_Ehdr ehdr;
+static Elf_Ehdr ehdr;
+static unsigned long shnum;
+static unsigned int shstrndx;
struct relocs {
uint32_t *offset;
@@ -241,9 +243,9 @@ static const char *sec_name(unsigned shndx)
{
const char *sec_strtab;
const char *name;
- sec_strtab = secs[ehdr.e_shstrndx].strtab;
+ sec_strtab = secs[shstrndx].strtab;
name = "<noname>";
- if (shndx < ehdr.e_shnum) {
+ if (shndx < shnum) {
name = sec_strtab + secs[shndx].shdr.sh_name;
}
else if (shndx == SHN_ABS) {
@@ -271,7 +273,7 @@ static const char *sym_name(const char *sym_strtab, Elf_Sym *sym)
static Elf_Sym *sym_lookup(const char *symname)
{
int i;
- for (i = 0; i < ehdr.e_shnum; i++) {
+ for (i = 0; i < shnum; i++) {
struct section *sec = &secs[i];
long nsyms;
char *strtab;
@@ -366,27 +368,41 @@ static void read_ehdr(FILE *fp)
ehdr.e_shnum = elf_half_to_cpu(ehdr.e_shnum);
ehdr.e_shstrndx = elf_half_to_cpu(ehdr.e_shstrndx);
- if ((ehdr.e_type != ET_EXEC) && (ehdr.e_type != ET_DYN)) {
+ shnum = ehdr.e_shnum;
+ shstrndx = ehdr.e_shstrndx;
+
+ if ((ehdr.e_type != ET_EXEC) && (ehdr.e_type != ET_DYN))
die("Unsupported ELF header type\n");
- }
- if (ehdr.e_machine != ELF_MACHINE) {
+ if (ehdr.e_machine != ELF_MACHINE)
die("Not for %s\n", ELF_MACHINE_NAME);
- }
- if (ehdr.e_version != EV_CURRENT) {
+ if (ehdr.e_version != EV_CURRENT)
die("Unknown ELF version\n");
- }
- if (ehdr.e_ehsize != sizeof(Elf_Ehdr)) {
+ if (ehdr.e_ehsize != sizeof(Elf_Ehdr))
die("Bad Elf header size\n");
- }
- if (ehdr.e_phentsize != sizeof(Elf_Phdr)) {
+ if (ehdr.e_phentsize != sizeof(Elf_Phdr))
die("Bad program header entry\n");
- }
- if (ehdr.e_shentsize != sizeof(Elf_Shdr)) {
+ if (ehdr.e_shentsize != sizeof(Elf_Shdr))
die("Bad section header entry\n");
+
+
+ if (shnum == SHN_UNDEF || shstrndx == SHN_XINDEX) {
+ Elf_Shdr shdr;
+
+ if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0)
+ die("Seek to %d failed: %s\n", ehdr.e_shoff, strerror(errno));
+
+ if (fread(&shdr, sizeof(shdr), 1, fp) != 1)
+ die("Cannot read initial ELF section header: %s\n", strerror(errno));
+
+ if (shnum == SHN_UNDEF)
+ shnum = elf_xword_to_cpu(shdr.sh_size);
+
+ if (shstrndx == SHN_XINDEX)
+ shstrndx = elf_word_to_cpu(shdr.sh_link);
}
- if (ehdr.e_shstrndx >= ehdr.e_shnum) {
+
+ if (shstrndx >= shnum)
die("String table index out of bounds\n");
- }
}
static void read_shdrs(FILE *fp)
@@ -394,20 +410,20 @@ static void read_shdrs(FILE *fp)
int i;
Elf_Shdr shdr;
- secs = calloc(ehdr.e_shnum, sizeof(struct section));
+ secs = calloc(shnum, sizeof(struct section));
if (!secs) {
die("Unable to allocate %d section headers\n",
- ehdr.e_shnum);
+ shnum);
}
if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0) {
die("Seek to %d failed: %s\n",
ehdr.e_shoff, strerror(errno));
}
- for (i = 0; i < ehdr.e_shnum; i++) {
+ for (i = 0; i < shnum; i++) {
struct section *sec = &secs[i];
if (fread(&shdr, sizeof(shdr), 1, fp) != 1)
die("Cannot read ELF section headers %d/%d: %s\n",
- i, ehdr.e_shnum, strerror(errno));
+ i, shnum, strerror(errno));
sec->shdr.sh_name = elf_word_to_cpu(shdr.sh_name);
sec->shdr.sh_type = elf_word_to_cpu(shdr.sh_type);
sec->shdr.sh_flags = elf_xword_to_cpu(shdr.sh_flags);
@@ -418,7 +434,7 @@ static void read_shdrs(FILE *fp)
sec->shdr.sh_info = elf_word_to_cpu(shdr.sh_info);
sec->shdr.sh_addralign = elf_xword_to_cpu(shdr.sh_addralign);
sec->shdr.sh_entsize = elf_xword_to_cpu(shdr.sh_entsize);
- if (sec->shdr.sh_link < ehdr.e_shnum)
+ if (sec->shdr.sh_link < shnum)
sec->link = &secs[sec->shdr.sh_link];
}
@@ -427,7 +443,7 @@ static void read_shdrs(FILE *fp)
static void read_strtabs(FILE *fp)
{
int i;
- for (i = 0; i < ehdr.e_shnum; i++) {
+ for (i = 0; i < shnum; i++) {
struct section *sec = &secs[i];
if (sec->shdr.sh_type != SHT_STRTAB) {
continue;
@@ -452,7 +468,7 @@ static void read_strtabs(FILE *fp)
static void read_symtabs(FILE *fp)
{
int i,j;
- for (i = 0; i < ehdr.e_shnum; i++) {
+ for (i = 0; i < shnum; i++) {
struct section *sec = &secs[i];
if (sec->shdr.sh_type != SHT_SYMTAB) {
continue;
@@ -485,7 +501,7 @@ static void read_symtabs(FILE *fp)
static void read_relocs(FILE *fp)
{
int i,j;
- for (i = 0; i < ehdr.e_shnum; i++) {
+ for (i = 0; i < shnum; i++) {
struct section *sec = &secs[i];
if (sec->shdr.sh_type != SHT_REL_TYPE) {
continue;
@@ -528,7 +544,7 @@ static void print_absolute_symbols(void)
printf("Absolute symbols\n");
printf(" Num: Value Size Type Bind Visibility Name\n");
- for (i = 0; i < ehdr.e_shnum; i++) {
+ for (i = 0; i < shnum; i++) {
struct section *sec = &secs[i];
char *sym_strtab;
int j;
@@ -566,7 +582,7 @@ static void print_absolute_relocs(void)
else
format = "%08"PRIx32" %08"PRIx32" %10s %08"PRIx32" %s\n";
- for (i = 0; i < ehdr.e_shnum; i++) {
+ for (i = 0; i < shnum; i++) {
struct section *sec = &secs[i];
struct section *sec_applies, *sec_symtab;
char *sym_strtab;
@@ -650,7 +666,7 @@ static void walk_relocs(int (*process)(struct section *sec, Elf_Rel *rel,
{
int i;
/* Walk through the relocations */
- for (i = 0; i < ehdr.e_shnum; i++) {
+ for (i = 0; i < shnum; i++) {
char *sym_strtab;
Elf_Sym *sh_symtab;
struct section *sec_applies, *sec_symtab;
@@ -706,7 +722,7 @@ static Elf_Addr per_cpu_load_addr;
static void percpu_init(void)
{
int i;
- for (i = 0; i < ehdr.e_shnum; i++) {
+ for (i = 0; i < shnum; i++) {
ElfW(Sym) *sym;
if (strcmp(sec_name(i), ".data..percpu"))
continue;
^ permalink raw reply related [flat|nested] 8+ messages in thread
end of thread, other threads:[~2019-04-19 19:01 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-11-29 13:51 [PATCH] x86/tools/relocs: fix big section header tables Artem Savkov
2018-11-29 14:23 ` Josh Poimboeuf
2018-11-29 15:22 ` Artem Savkov
2018-11-29 15:32 ` Josh Poimboeuf
2018-11-29 15:56 ` [PATCH v2] " Artem Savkov
2018-11-29 15:57 ` Josh Poimboeuf
2019-01-11 19:09 ` Joe Lawrence
2019-04-19 19:01 ` [tip:x86/build] x86/tools/relocs: Fix " tip-bot for Artem Savkov
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