path: root/common/image.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/image.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/image.c')
1 files changed, 3 insertions, 3 deletions
diff --git a/common/image.c b/common/image.c
index 2b6007e9c..6d8833e81 100644
--- a/common/image.c
+++ b/common/image.c
@@ -60,7 +60,7 @@ static int fit_check_ramdisk (const void *fit, int os_noffset,
-extern int do_bdinfo(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]);
+extern int do_bdinfo(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]);
@@ -756,7 +756,7 @@ int genimg_has_config (bootm_headers_t *images)
* 1, if ramdisk image is found but corrupted, or invalid
* rd_start and rd_end are set to 0 if no ramdisk exists
-int boot_get_ramdisk (int argc, char *argv[], bootm_headers_t *images,
+int boot_get_ramdisk (int argc, char * const argv[], bootm_headers_t *images,
uint8_t arch, ulong *rd_start, ulong *rd_end)
ulong rd_addr, rd_load;
@@ -1279,7 +1279,7 @@ error:
* 1, if fdt image is found but corrupted
* of_flat_tree and of_size are set to 0 if no fdt exists
-int boot_get_fdt (int flag, int argc, char *argv[], bootm_headers_t *images,
+int boot_get_fdt (int flag, int argc, char * const argv[], bootm_headers_t *images,
char **of_flat_tree, ulong *of_size)
const image_header_t *fdt_hdr;