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authorJosh Poimboeuf <jpoimboe@redhat.com>2017-06-28 17:11:07 +0200
committerIngo Molnar <mingo@kernel.org>2017-06-30 10:19:19 +0200
commitbaa41469a7b992c1e3db2a39854219cc7442e48f (patch)
tree1a8e43a0d5e27db457c1cc6f8a4510b258b46bee /tools/objtool/elf.c
parentobjtool, x86: Add several functions and files to the objtool whitelist (diff)
downloadlinux-baa41469a7b992c1e3db2a39854219cc7442e48f.tar.xz
linux-baa41469a7b992c1e3db2a39854219cc7442e48f.zip
objtool: Implement stack validation 2.0
This is a major rewrite of objtool. Instead of only tracking frame pointer changes, it now tracks all stack-related operations, including all register saves/restores. In addition to making stack validation more robust, this also paves the way for undwarf generation. Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: live-patching@vger.kernel.org Link: http://lkml.kernel.org/r/678bd94c0566c6129bcc376cddb259c4c5633004.1498659915.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'tools/objtool/elf.c')
-rw-r--r--tools/objtool/elf.c59
1 files changed, 28 insertions, 31 deletions
diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index d897702ce742..1a7e8aa2af58 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -37,6 +37,9 @@
#define ELF_C_READ_MMAP ELF_C_READ
#endif
+#define WARN_ELF(format, ...) \
+ WARN(format ": %s", ##__VA_ARGS__, elf_errmsg(-1))
+
struct section *find_section_by_name(struct elf *elf, const char *name)
{
struct section *sec;
@@ -139,12 +142,12 @@ static int read_sections(struct elf *elf)
int i;
if (elf_getshdrnum(elf->elf, &sections_nr)) {
- perror("elf_getshdrnum");
+ WARN_ELF("elf_getshdrnum");
return -1;
}
if (elf_getshdrstrndx(elf->elf, &shstrndx)) {
- perror("elf_getshdrstrndx");
+ WARN_ELF("elf_getshdrstrndx");
return -1;
}
@@ -165,37 +168,36 @@ static int read_sections(struct elf *elf)
s = elf_getscn(elf->elf, i);
if (!s) {
- perror("elf_getscn");
+ WARN_ELF("elf_getscn");
return -1;
}
sec->idx = elf_ndxscn(s);
if (!gelf_getshdr(s, &sec->sh)) {
- perror("gelf_getshdr");
+ WARN_ELF("gelf_getshdr");
return -1;
}
sec->name = elf_strptr(elf->elf, shstrndx, sec->sh.sh_name);
if (!sec->name) {
- perror("elf_strptr");
+ WARN_ELF("elf_strptr");
return -1;
}
- sec->elf_data = elf_getdata(s, NULL);
- if (!sec->elf_data) {
- perror("elf_getdata");
+ sec->data = elf_getdata(s, NULL);
+ if (!sec->data) {
+ WARN_ELF("elf_getdata");
return -1;
}
- if (sec->elf_data->d_off != 0 ||
- sec->elf_data->d_size != sec->sh.sh_size) {
+ if (sec->data->d_off != 0 ||
+ sec->data->d_size != sec->sh.sh_size) {
WARN("unexpected data attributes for %s", sec->name);
return -1;
}
- sec->data = (unsigned long)sec->elf_data->d_buf;
- sec->len = sec->elf_data->d_size;
+ sec->len = sec->data->d_size;
}
/* sanity check, one more call to elf_nextscn() should return NULL */
@@ -232,15 +234,15 @@ static int read_symbols(struct elf *elf)
sym->idx = i;
- if (!gelf_getsym(symtab->elf_data, i, &sym->sym)) {
- perror("gelf_getsym");
+ if (!gelf_getsym(symtab->data, i, &sym->sym)) {
+ WARN_ELF("gelf_getsym");
goto err;
}
sym->name = elf_strptr(elf->elf, symtab->sh.sh_link,
sym->sym.st_name);
if (!sym->name) {
- perror("elf_strptr");
+ WARN_ELF("elf_strptr");
goto err;
}
@@ -322,8 +324,8 @@ static int read_relas(struct elf *elf)
}
memset(rela, 0, sizeof(*rela));
- if (!gelf_getrela(sec->elf_data, i, &rela->rela)) {
- perror("gelf_getrela");
+ if (!gelf_getrela(sec->data, i, &rela->rela)) {
+ WARN_ELF("gelf_getrela");
return -1;
}
@@ -362,12 +364,6 @@ struct elf *elf_open(const char *name)
INIT_LIST_HEAD(&elf->sections);
- elf->name = strdup(name);
- if (!elf->name) {
- perror("strdup");
- goto err;
- }
-
elf->fd = open(name, O_RDONLY);
if (elf->fd == -1) {
perror("open");
@@ -376,12 +372,12 @@ struct elf *elf_open(const char *name)
elf->elf = elf_begin(elf->fd, ELF_C_READ_MMAP, NULL);
if (!elf->elf) {
- perror("elf_begin");
+ WARN_ELF("elf_begin");
goto err;
}
if (!gelf_getehdr(elf->elf, &elf->ehdr)) {
- perror("gelf_getehdr");
+ WARN_ELF("gelf_getehdr");
goto err;
}
@@ -407,6 +403,12 @@ void elf_close(struct elf *elf)
struct symbol *sym, *tmpsym;
struct rela *rela, *tmprela;
+ if (elf->elf)
+ elf_end(elf->elf);
+
+ if (elf->fd > 0)
+ close(elf->fd);
+
list_for_each_entry_safe(sec, tmpsec, &elf->sections, list) {
list_for_each_entry_safe(sym, tmpsym, &sec->symbol_list, list) {
list_del(&sym->list);
@@ -421,11 +423,6 @@ void elf_close(struct elf *elf)
list_del(&sec->list);
free(sec);
}
- if (elf->name)
- free(elf->name);
- if (elf->fd > 0)
- close(elf->fd);
- if (elf->elf)
- elf_end(elf->elf);
+
free(elf);
}