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authorMike Frysinger <vapier@gentoo.org>2016-01-03 16:32:47 -0500
committerMike Frysinger <vapier@gentoo.org>2016-01-03 16:32:47 -0500
commit9b36cb0609e6553f2c89c0b5909aa8c6482f9c7f (patch)
tree51e1cfff8bc8887043ba80891111c3da75aa1fc8
parentbuild: include -Wmisleading-indentation when available (diff)
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dumpelf: improve decoding
- push down section header validity checks (previous one was too strict) - fix section header walking (was missing braces in for loop) - dump all of the pad bytes in the elf header - expand program header output and decode/explain more fields - use uintptr_t for doing pointer math - handle SHT_NOBITS better
-rw-r--r--dumpelf.c102
1 files changed, 76 insertions, 26 deletions
diff --git a/dumpelf.c b/dumpelf.c
index 8abad61..d765164 100644
--- a/dumpelf.c
+++ b/dumpelf.c
@@ -111,10 +111,7 @@ static void dumpelf(const char *filename, long file_cnt)
} \
offset = EGET(strtbl->sh_offset); \
for (i = 0; i < shnum; ++i, ++shdr) \
- if (!VALID_SHDR(elf, shdr)) { \
- printf(" /* corrupt section headers ! */ "); \
- break; \
- } \
+ /* Don't use VALID_SHDR as we want to decode the fields */ \
dump_shdr(elf, shdr, i, elf->vdata + offset + EGET(shdr->sh_name)); \
}
DUMP_SHDRS(32)
@@ -155,6 +152,7 @@ static void dumpelf(const char *filename, long file_cnt)
/* get out of here */
unreadelf(elf);
}
+
static void dump_ehdr(elfobj *elf, const void *ehdr_void)
{
#define DUMP_EHDR(B) \
@@ -168,8 +166,7 @@ static void dump_ehdr(elfobj *elf, const void *ehdr_void)
"\t\t/* [%i] EI_VERSION: */ %i , /* (%s) */\n" \
"\t\t/* [%i] EI_OSABI: */ %i , /* (%s) */\n" \
"\t\t/* [%i] EI_ABIVERSION: */ %i ,\n" \
- "\t\t/* [%i] EI_PAD: */ 0x%02X /* x %i bytes */\n" \
- /* "\t\t/ [%i] EI_BRAND: / 0x%02X\n" */ \
+ "\t\t/* [%i-%i] EI_PAD: */ 0x%X, 0x%X, 0x%X, 0x%X, 0x%X, 0x%X, 0x%X,\n" \
"\t},\n", \
EI_MAG0, (unsigned int)ehdr->e_ident[EI_MAG0], ehdr->e_ident[EI_MAG1], ehdr->e_ident[EI_MAG2], ehdr->e_ident[EI_MAG3], \
EI_CLASS, (int)ehdr->e_ident[EI_CLASS], get_elfeitype(EI_CLASS, ehdr->e_ident[EI_CLASS]), \
@@ -177,18 +174,25 @@ static void dump_ehdr(elfobj *elf, const void *ehdr_void)
EI_VERSION, (int)ehdr->e_ident[EI_VERSION], get_elfeitype(EI_VERSION, ehdr->e_ident[EI_VERSION]), \
EI_OSABI, (int)ehdr->e_ident[EI_OSABI], get_elfeitype(EI_OSABI, ehdr->e_ident[EI_OSABI]), \
EI_ABIVERSION, (int)ehdr->e_ident[EI_ABIVERSION], \
- EI_PAD, (unsigned int)ehdr->e_ident[EI_PAD], EI_NIDENT - EI_PAD \
- /* EI_BRAND, ehdr->e_ident[EI_BRAND] */ \
+ EI_PAD, EI_NIDENT - 1, \
+ (unsigned int)ehdr->e_ident[EI_PAD + 0], \
+ (unsigned int)ehdr->e_ident[EI_PAD + 1], \
+ (unsigned int)ehdr->e_ident[EI_PAD + 2], \
+ (unsigned int)ehdr->e_ident[EI_PAD + 3], \
+ (unsigned int)ehdr->e_ident[EI_PAD + 4], \
+ (unsigned int)ehdr->e_ident[EI_PAD + 5], \
+ (unsigned int)ehdr->e_ident[EI_PAD + 6] \
); \
printf("\t.e_type = %-10i , /* (%s) */\n", (int)EGET(ehdr->e_type), get_elfetype(elf)); \
printf("\t.e_machine = %-10i , /* (%s) */\n", (int)EGET(ehdr->e_machine), get_elfemtype(elf)); \
- printf("\t.e_version = %-10i ,\n", (int)EGET(ehdr->e_version)); \
- printf("\t.e_entry = 0x%-8lX ,\n", (unsigned long)EGET(ehdr->e_entry)); \
+ printf("\t.e_version = %-10i , /* (%s) */\n", (int)EGET(ehdr->e_version), get_elfeitype(EI_VERSION, EGET(ehdr->e_version))); \
+ printf("\t.e_entry = 0x%-8lX , /* (start address at runtime) */\n", (unsigned long)EGET(ehdr->e_entry)); \
printf("\t.e_phoff = %-10li , /* (bytes into file) */\n", (unsigned long)EGET(ehdr->e_phoff)); \
printf("\t.e_shoff = %-10li , /* (bytes into file) */\n", (unsigned long)EGET(ehdr->e_shoff)); \
printf("\t.e_flags = 0x%-8X ,\n", (unsigned int)EGET(ehdr->e_flags)); \
printf("\t.e_ehsize = %-10i , /* (bytes) */\n", (int)EGET(ehdr->e_ehsize)); \
printf("\t.e_phentsize = %-10i , /* (bytes) */\n", (int)EGET(ehdr->e_phentsize)); \
+ /* TODO: Handle PN_XNUM */ \
printf("\t.e_phnum = %-10i , /* (program headers) */\n", (int)EGET(ehdr->e_phnum)); \
printf("\t.e_shentsize = %-10i , /* (bytes) */\n", (int)EGET(ehdr->e_shentsize)); \
printf("\t.e_shnum = %-10i , /* (section headers) */\n", (int)EGET(ehdr->e_shnum)); \
@@ -198,28 +202,63 @@ static void dump_ehdr(elfobj *elf, const void *ehdr_void)
DUMP_EHDR(32)
DUMP_EHDR(64)
}
+
+static const char *dump_p_flags(uint32_t type, uint32_t flags)
+{
+ static char buf[1024];
+ char *p = buf;
+ p[0] = p[1] = p[2] = '\0';
+
+ if (flags & PF_R)
+ p = stpcpy(p, " | PF_R");
+ if (flags & PF_W)
+ p = stpcpy(p, " | PF_W");
+ if (flags & PF_X)
+ p = stpcpy(p, " | PF_X");
+ flags &= ~(PF_R | PF_W | PF_X);
+
+ switch (type) {
+ case PT_PAX_FLAGS:
+#define X(b) if (flags & b) { p = stpcpy(p, " | " #b); flags &= ~b; }
+ X(PF_PAGEEXEC) X(PF_NOPAGEEXEC)
+ X(PF_SEGMEXEC) X(PF_NOSEGMEXEC)
+ X(PF_MPROTECT) X(PF_NOMPROTECT)
+ X(PF_RANDEXEC) X(PF_NORANDEXEC)
+ X(PF_EMUTRAMP) X(PF_NOEMUTRAMP)
+ X(PF_RANDMMAP) X(PF_NORANDMMAP)
+#undef X
+ break;
+ }
+
+ if (flags)
+ sprintf(p, " | 0x%X", flags);
+
+ return buf + 3;
+}
static void dump_phdr(elfobj *elf, const void *phdr_void, long phdr_cnt)
{
#define DUMP_PHDR(B) \
if (elf->elf_class == ELFCLASS ## B) { \
const Elf ## B ## _Phdr *phdr = PHDR ## B (phdr_void); \
- switch (EGET(phdr->p_type)) { \
+ uint32_t p_type = EGET(phdr->p_type); \
+ switch (p_type) { \
case PT_DYNAMIC: phdr_dynamic_void = phdr_void; break; \
} \
- printf("/* Program Header #%li 0x%lX */\n{\n", phdr_cnt, (unsigned long)phdr_void - (unsigned long)elf->data); \
- printf("\t.p_type = %-10li , /* [%s] */\n", (long)EGET(phdr->p_type), get_elfptype(EGET(phdr->p_type))); \
- printf("\t.p_offset = %-10li ,\n", (long)EGET(phdr->p_offset)); \
- printf("\t.p_vaddr = 0x%-8lX ,\n", (unsigned long)EGET(phdr->p_vaddr)); \
- printf("\t.p_paddr = 0x%-8lX ,\n", (unsigned long)EGET(phdr->p_paddr)); \
- printf("\t.p_filesz = %-10li ,\n", (long)EGET(phdr->p_filesz)); \
- printf("\t.p_memsz = %-10li ,\n", (long)EGET(phdr->p_memsz)); \
- printf("\t.p_flags = %-10li ,\n", (long)EGET(phdr->p_flags)); \
- printf("\t.p_align = %-10li\n", (long)EGET(phdr->p_align)); \
+ printf("/* Program Header #%li 0x%lX */\n{\n", phdr_cnt, (uintptr_t)phdr_void - (uintptr_t)elf->data); \
+ printf("\t.p_type = %-10li , /* [%s] */\n", (long)p_type, get_elfptype(p_type)); \
+ printf("\t.p_offset = %-10li , /* (bytes into file) */\n", (long)EGET(phdr->p_offset)); \
+ printf("\t.p_vaddr = 0x%-8lX , /* (virtual addr at runtime) */\n", (unsigned long)EGET(phdr->p_vaddr)); \
+ printf("\t.p_paddr = 0x%-8lX , /* (physical addr at runtime) */\n", (unsigned long)EGET(phdr->p_paddr)); \
+ printf("\t.p_filesz = %-10li , /* (bytes in file) */\n", (long)EGET(phdr->p_filesz)); \
+ printf("\t.p_memsz = %-10li , /* (bytes in mem at runtime) */\n", (long)EGET(phdr->p_memsz)); \
+ printf("\t.p_flags = 0x%-8lX , /* %s */\n", (unsigned long)EGET(phdr->p_flags), dump_p_flags(p_type, EGET(phdr->p_flags))); \
+ printf("\t.p_align = %-10li , /* (min mem alignment in bytes) */\n", (long)EGET(phdr->p_align)); \
printf("},\n"); \
}
DUMP_PHDR(32)
DUMP_PHDR(64)
}
+
static void dump_shdr(elfobj *elf, const void *shdr_void, long shdr_cnt, const char *name)
{
unsigned long i;
@@ -233,22 +272,31 @@ static void dump_shdr(elfobj *elf, const void *shdr_void, long shdr_cnt, const c
#define DUMP_SHDR(B) \
if (elf->elf_class == ELFCLASS ## B) { \
const Elf ## B ## _Shdr *shdr = SHDR ## B (shdr_void); \
+ Elf ## B ## _Off offset = EGET(shdr->sh_offset); \
uint32_t type = EGET(shdr->sh_type); \
uint ## B ## _t size = EGET(shdr->sh_size); \
+ \
printf("/* Section Header #%li '%s' 0x%lX */\n{\n", \
- shdr_cnt, name, (unsigned long)shdr_void - (unsigned long)elf->data); \
+ shdr_cnt, name, (uintptr_t)shdr_void - (uintptr_t)elf->data); \
printf("\t.sh_name = %-10i ,\n", (int)EGET(shdr->sh_name)); \
printf("\t.sh_type = %-10i , /* [%s] */\n", (int)EGET(shdr->sh_type), get_elfshttype(type)); \
printf("\t.sh_flags = %-10li ,\n", (long)EGET(shdr->sh_flags)); \
printf("\t.sh_addr = 0x%-8lX ,\n", (unsigned long)EGET(shdr->sh_addr)); \
- printf("\t.sh_offset = %-10i , /* (bytes) */\n", (int)EGET(shdr->sh_offset)); \
- printf("\t.sh_size = %-10li , /* (bytes) */\n", (long)EGET(shdr->sh_size)); \
+ printf("\t.sh_offset = %-10li , /* (bytes) */\n", (long)offset); \
+ printf("\t.sh_size = %-10lu , /* (bytes) */\n", (unsigned long)size); \
printf("\t.sh_link = %-10i ,\n", (int)EGET(shdr->sh_link)); \
printf("\t.sh_info = %-10i ,\n", (int)EGET(shdr->sh_info)); \
printf("\t.sh_addralign = %-10li ,\n", (long)EGET(shdr->sh_addralign)); \
printf("\t.sh_entsize = %-10li\n", (long)EGET(shdr->sh_entsize)); \
- if (size && be_verbose) { \
- void *vdata = elf->vdata + EGET(shdr->sh_offset); \
+ \
+ if (type == SHT_NOBITS) { \
+ /* Special case so we can do valid check next. */ \
+ if (be_verbose) \
+ printf("\t/* NOBITS sections do not occupy the file. */\n"); \
+ } else if (!(offset < (uint64_t)elf->len && size < (uint64_t)elf->len && offset <= elf->len - size)) { \
+ printf(" /* corrupt section header ! */ "); \
+ } else if (size && be_verbose) { \
+ void *vdata = elf->vdata + offset; \
unsigned char *data = vdata; \
switch (type) { \
case SHT_PROGBITS: { \
@@ -258,6 +306,7 @@ static void dump_shdr(elfobj *elf, const void *shdr_void, long shdr_cnt, const c
} \
if (strcmp(name, ".comment") != 0) \
break; \
+ break; \
} \
case SHT_STRTAB: { \
char b; \
@@ -315,6 +364,7 @@ static void dump_shdr(elfobj *elf, const void *shdr_void, long shdr_cnt, const c
DUMP_SHDR(32)
DUMP_SHDR(64)
}
+
static void dump_dyn(elfobj *elf, const void *dyn_void, long dyn_cnt)
{
#define DUMP_DYN(B) \
@@ -322,7 +372,7 @@ static void dump_dyn(elfobj *elf, const void *dyn_void, long dyn_cnt)
const Elf ## B ## _Dyn *dyn = dyn_void; \
unsigned long tag = EGET(dyn->d_tag); \
printf("/* Dynamic tag #%li '%s' 0x%lX */\n{\n", \
- dyn_cnt, get_elfdtype(tag), (unsigned long)dyn_void - (unsigned long)elf->data); \
+ dyn_cnt, get_elfdtype(tag), (uintptr_t)dyn_void - (uintptr_t)elf->data); \
printf("\t.d_tag = 0x%-8lX ,\n", tag); \
printf("\t.d_un = {\n"); \
printf("\t\t.d_val = 0x%-8lX ,\n", (unsigned long)EGET(dyn->d_un.d_val)); \