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authorWolfgang Denk <wd@denx.de>2010-06-28 22:00:46 +0200
committerWolfgang Denk <wd@denx.de>2010-07-04 23:55:42 +0200
commit54841ab50c20d6fa6c9cc3eb826989da3a22d934 (patch)
tree400f22f0a12ff0ae6c472bed6ac648befc1744a2 /arch/mips
parentb218ccb5435e64ac2318bb8b6c9594ef1cc724cd (diff)
downloadu-boot-linaro-stable-54841ab50c20d6fa6c9cc3eb826989da3a22d934.tar.gz
Make sure that argv[] argument pointers are not modified.
The hush shell dynamically allocates (and re-allocates) memory for the argument strings in the "char *argv[]" argument vector passed to commands. Any code that modifies these pointers will cause serious corruption of the malloc data structures and crash U-Boot, so make sure the compiler can check that no such modifications are being done by changing the code into "char * const argv[]". This modification is the result of debugging a strange crash caused after adding a new command, which used the following argument processing code which has been working perfectly fine in all Unix systems since version 6 - but not so in U-Boot: int main (int argc, char **argv) { while (--argc > 0 && **++argv == '-') { /* ====> */ while (*++*argv) { switch (**argv) { case 'd': debug++; break; ... default: usage (); } } } ... } The line marked "====>" will corrupt the malloc data structures and usually cause U-Boot to crash when the next command gets executed by the shell. With the modification, the compiler will prevent this with an error: increment of read-only location '*argv' N.B.: The code above can be trivially rewritten like this: while (--argc > 0 && **++argv == '-') { char *arg = *argv; while (*++arg) { switch (*arg) { ... Signed-off-by: Wolfgang Denk <wd@denx.de> Acked-by: Mike Frysinger <vapier@gentoo.org>
Diffstat (limited to 'arch/mips')
-rw-r--r--arch/mips/cpu/cpu.c2
-rw-r--r--arch/mips/lib/bootm.c2
-rw-r--r--arch/mips/lib/bootm_qemu_mips.c2
3 files changed, 3 insertions, 3 deletions
diff --git a/arch/mips/cpu/cpu.c b/arch/mips/cpu/cpu.c
index d5a16047d..3ae397c8e 100644
--- a/arch/mips/cpu/cpu.c
+++ b/arch/mips/cpu/cpu.c
@@ -42,7 +42,7 @@ void __attribute__((weak)) _machine_restart(void)
{
}
-int do_reset(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_reset(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
_machine_restart();
diff --git a/arch/mips/lib/bootm.c b/arch/mips/lib/bootm.c
index 54af24cba..40a564718 100644
--- a/arch/mips/lib/bootm.c
+++ b/arch/mips/lib/bootm.c
@@ -43,7 +43,7 @@ static int linux_env_idx;
static void linux_params_init (ulong start, char * commandline);
static void linux_env_set (char * env_name, char * env_val);
-int do_bootm_linux(int flag, int argc, char *argv[], bootm_headers_t *images)
+int do_bootm_linux(int flag, int argc, char * const argv[], bootm_headers_t *images)
{
void (*theKernel) (int, char **, char **, int *);
char *commandline = getenv ("bootargs");
diff --git a/arch/mips/lib/bootm_qemu_mips.c b/arch/mips/lib/bootm_qemu_mips.c
index cc70fa93f..f1906c677 100644
--- a/arch/mips/lib/bootm_qemu_mips.c
+++ b/arch/mips/lib/bootm_qemu_mips.c
@@ -29,7 +29,7 @@
DECLARE_GLOBAL_DATA_PTR;
-int do_bootm_linux(int flag, int argc, char *argv[], bootm_headers_t *images)
+int do_bootm_linux(int flag, int argc, char * const argv[], bootm_headers_t *images)
{
void (*theKernel) (int, char **, char **, int *);
char *bootargs = getenv ("bootargs");