path: root/common/cmd_nand.c
diff options
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 /common/cmd_nand.c
parentb218ccb5435e64ac2318bb8b6c9594ef1cc724cd (diff)
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 'common/cmd_nand.c')
1 files changed, 3 insertions, 3 deletions
diff --git a/common/cmd_nand.c b/common/cmd_nand.c
index f611fd771..ea80555ef 100644
--- a/common/cmd_nand.c
+++ b/common/cmd_nand.c
@@ -90,7 +90,7 @@ static inline int str2long(char *p, ulong *num)
static int
-arg_off_size(int argc, char *argv[], nand_info_t *nand, ulong *off, size_t *size)
+arg_off_size(int argc, char * const argv[], nand_info_t *nand, ulong *off, size_t *size)
int idx = nand_curr_device;
@@ -204,7 +204,7 @@ static void nand_print_info(int idx)
nand->name, nand->erasesize >> 10);
-int do_nand(cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
+int do_nand(cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
int i, dev, ret = 0;
ulong addr, off;
@@ -599,7 +599,7 @@ static int nand_load_image(cmd_tbl_t *cmdtp, nand_info_t *nand,
return 0;
-int do_nandboot(cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
+int do_nandboot(cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
char *boot_device = NULL;
int idx;