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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/powerpc/lib
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/powerpc/lib')
-rw-r--r--arch/powerpc/lib/bootm.c4
-rw-r--r--arch/powerpc/lib/kgdb.c2
2 files changed, 3 insertions, 3 deletions
diff --git a/arch/powerpc/lib/bootm.c b/arch/powerpc/lib/bootm.c
index 6702df51a..306412114 100644
--- a/arch/powerpc/lib/bootm.c
+++ b/arch/powerpc/lib/bootm.c
@@ -47,7 +47,7 @@
DECLARE_GLOBAL_DATA_PTR;
-extern int do_reset (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]);
+extern int do_reset (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]);
extern ulong get_effective_memsize(void);
static ulong get_sp (void);
static void set_clocks_in_mhz (bd_t *kbd);
@@ -297,7 +297,7 @@ static int boot_body_linux(bootm_headers_t *images)
}
__attribute__((noinline))
-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)
{
int ret;
diff --git a/arch/powerpc/lib/kgdb.c b/arch/powerpc/lib/kgdb.c
index d3eb1f35a..1ec68184b 100644
--- a/arch/powerpc/lib/kgdb.c
+++ b/arch/powerpc/lib/kgdb.c
@@ -313,7 +313,7 @@ kgdb_putregs(struct pt_regs *regs, char *buf, int length)
the debugger. */
void
-kgdb_breakpoint(int argc, char *argv[])
+kgdb_breakpoint(int argc, char * const argv[])
{
asm(" .globl breakinst\n\
breakinst: .long 0x7d821008\n\