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objtool: Implement stack validation 2.0

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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>
This commit is contained in:
Josh Poimboeuf
2017-06-28 10:11:07 -05:00
committed by Ingo Molnar
parent c207aee480
commit baa41469a7
11 changed files with 1133 additions and 323 deletions
Download Patch File Download Diff File Expand all files Collapse all files

59
tools/objtool/elf.c
View File

@@ -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);
}