Bernhard Walle wrote:
* Dave Anderson <anderson@xxxxxxxxxx> [2007-12-21 16:00]:
Maybe it should cut down on the initial 32/64-bit verifier
to check only the ELFMAG and the bytes in the E_IDENT string.
Then inside of the 32 and 64 bit blocks, first check for
the architecture and bail out with a "arch-mismatch" error.
(although in doing so, the e_machine switch statement would
have to have cases for each arch and its byte-toggled version)
Then the current endian check could be made, and if it
doesn't match bail out with an "endian" error.
And then for sanity's sake, the remainder of header checks
could be done, which if we get that far, are pretty much
guaranteed to never happen.
Sounds sane. What about this:
Looks reasonable.
BTW, since is_netdump() gets called twice, first
directly and then via is_kdump(), do the error
messages get printed twice?
---
defs.h | 3 +
netdump.c | 119 ++++++++++++++++++++++++++++++++++++++++++++++----------------
tools.c | 9 ++++
3 files changed, 100 insertions(+), 31 deletions(-)
--- a/defs.h
+++ b/defs.h
@@ -3198,7 +3198,8 @@ void stall(ulong);
char *pages_to_size(ulong, char *);
int clean_arg(void);
int empty_list(ulong);
-int machine_type(char *);
+int machine_type(const char *);
+int is_big_endian(void);
void command_not_supported(void);
void option_not_supported(int);
void please_wait(char *);
--- a/netdump.c
+++ b/netdump.c
@@ -36,6 +36,47 @@ static void check_dumpfile_size(char *);
#define ELFREAD 0
#define MIN_PAGE_SIZE (4096)
+#define TOGGLE_ENDIAN_16(val) \
+ (((val >> 8) & 0xff) | ((val << 8) & 0xff00))
+
+
+
+/*
+ * Checks if the machine type of the host matches required_type.
+ * If not, it prints a short error message for the user.
+ */
+static int machine_type_error(const char *required_type)
+{
+ if (machine_type(required_type))
+ return 1;
+ else {
+ fprintf(stderr, "Looks like a valid ELF dump, but host "
+ "architecture (%s) doesn't match dump "
+ "architecture (%s).\n",
+ MACHINE_TYPE, required_type);
+ return 0;
+ }
+}
+
+/*
+ * Returns endianess in a string
+ */
+static const char *endianess_to_string(int big_endian)
+{
+ return big_endian ? "BE" : "LE";
+}
+
+/*
+ * Prints an endian error.
+ */
+static void endian_error(int target_big_endian)
+{
+ fprintf(stderr, "Looks like a valid ELF dump, but host "
+ "endianess (%s) doesn't match target "
+ "endianess (%s)\n",
+ endianess_to_string(is_big_endian()),
+ endianess_to_string(target_big_endian));
+}
/*
* Determine whether a file is a netdump/diskdump/kdump creation,
@@ -99,21 +140,34 @@ is_netdump(char *file, ulong source_quer
* is obviously subject to change.
*/
if (STRNEQ(elf32->e_ident, ELFMAG) &&
- (elf32->e_ident[EI_CLASS] == ELFCLASS32) &&
- (elf32->e_ident[EI_DATA] == ELFDATA2LSB) &&
- (elf32->e_ident[EI_VERSION] == EV_CURRENT) &&
- (elf32->e_type == ET_CORE) &&
- (elf32->e_version == EV_CURRENT) &&
- (elf32->e_phnum >= 2)) {
+ (elf32->e_ident[EI_CLASS] == ELFCLASS32)) {
+
+ /* check arch */
switch (elf32->e_machine)
{
case EM_386:
- if (machine_type("X86"))
- break;
+ case TOGGLE_ENDIAN_16(EM_386):
+ if (!machine_type_error("X86"))
+ goto bailout;
+ break;
default:
goto bailout;
}
+ /* check endianess */
+ if ((elf32->e_ident[EI_DATA] == ELFDATA2LSB && is_big_endian()) ||
+ (elf32->e_ident[EI_DATA] == ELFDATA2MSB && !is_big_endian())) {
+ endian_error(elf32->e_ident[EI_DATA] == ELFDATA2MSB);
+ goto bailout;
+ }
+
+ /* check other ELF headers */
+ if ((elf32->e_ident[EI_VERSION] != EV_CURRENT) ||
+ (elf32->e_type != ET_CORE) ||
+ (elf32->e_version != EV_CURRENT) ||
+ (elf32->e_phnum < 2))
+ goto bailout;
+
load32 = (Elf32_Phdr *)
&header[sizeof(Elf32_Ehdr)+sizeof(Elf32_Phdr)];
size = (size_t)load32->p_offset;
@@ -124,45 +178,52 @@ is_netdump(char *file, ulong source_quer
else
tmp_flags |= NETDUMP_ELF32;
} else if (STRNEQ(elf64->e_ident, ELFMAG) &&
- (elf64->e_ident[EI_CLASS] == ELFCLASS64) &&
- (elf64->e_ident[EI_VERSION] == EV_CURRENT) &&
- (elf64->e_type == ET_CORE) &&
- (elf64->e_version == EV_CURRENT) &&
- (elf64->e_phnum >= 2)) {
+ (elf64->e_ident[EI_CLASS] == ELFCLASS64)) {
+
+ /* check arch */
switch (elf64->e_machine)
{
case EM_IA_64:
- if ((elf64->e_ident[EI_DATA] == ELFDATA2LSB) &&
- machine_type("IA64"))
- break;
- else
+ case TOGGLE_ENDIAN_16(EM_IA_64):
+ if (!machine_type_error("IA64"))
goto bailout;
+ break;
case EM_PPC64:
- if ((elf64->e_ident[EI_DATA] == ELFDATA2MSB) &&
- machine_type("PPC64"))
- break;
- else
+ case TOGGLE_ENDIAN_16(EM_PPC64):
+ if (!machine_type_error("PPC64"))
goto bailout;
+ break;
case EM_X86_64:
- if ((elf64->e_ident[EI_DATA] == ELFDATA2LSB) &&
- machine_type("X86_64"))
- break;
- else
+ case TOGGLE_ENDIAN_16(EM_X86_64):
+ if (!machine_type_error("X86_64"))
goto bailout;
+ break;
case EM_386:
- if ((elf64->e_ident[EI_DATA] == ELFDATA2LSB) &&
- machine_type("X86"))
- break;
- else
+ case TOGGLE_ENDIAN_16(EM_386):
+ if (!machine_type_error("X86"))
goto bailout;
+ break;
default:
goto bailout;
}
+ /* check endianess */
+ if ((elf64->e_ident[EI_DATA] == ELFDATA2LSB && is_big_endian()) ||
+ (elf64->e_ident[EI_DATA] == ELFDATA2MSB && !is_big_endian())) {
+ endian_error(elf64->e_ident[EI_DATA] == ELFDATA2MSB);
+ goto bailout;
+ }
+
+ if ((elf64->e_ident[EI_VERSION] != EV_CURRENT) ||
+ (elf64->e_type != ET_CORE) ||
+ (elf64->e_version != EV_CURRENT) ||
+ (elf64->e_phnum < 2))
+ goto bailout;
+
load64 = (Elf64_Phdr *)
&header[sizeof(Elf64_Ehdr)+sizeof(Elf64_Phdr)];
size = (size_t)load64->p_offset;
--- a/tools.c
+++ b/tools.c
@@ -4518,11 +4518,18 @@ empty_list(ulong list_head_addr)
}
int
-machine_type(char *type)
+machine_type(const char *type)
{
return STREQ(MACHINE_TYPE, type);
}
+int
+is_big_endian(void)
+{
+ unsigned short value = 0xff;
+ return *((unsigned char *)&value) != 0xff;
+}
+
void
command_not_supported()
{
--
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