From 54841ab50c20d6fa6c9cc3eb826989da3a22d934 Mon Sep 17 00:00:00 2001 From: Wolfgang Denk Date: Mon, 28 Jun 2010 22:00:46 +0200 Subject: 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 Acked-by: Mike Frysinger --- common/cmd_yaffs2.c | 24 ++++++++++++------------ 1 file changed, 12 insertions(+), 12 deletions(-) (limited to 'common/cmd_yaffs2.c') diff --git a/common/cmd_yaffs2.c b/common/cmd_yaffs2.c index d448d0483..7c01ea2a2 100644 --- a/common/cmd_yaffs2.c +++ b/common/cmd_yaffs2.c @@ -24,7 +24,7 @@ extern void cmd_yaffs_mv(const char *oldPath, const char *newPath); extern int yaffs_DumpDevStruct(const char *path); -int do_ymount (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +int do_ymount (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { char *mtpoint = argv[1]; cmd_yaffs_mount(mtpoint); @@ -32,7 +32,7 @@ int do_ymount (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) return(0); } -int do_yumount (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +int do_yumount (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { char *mtpoint = argv[1]; cmd_yaffs_umount(mtpoint); @@ -40,7 +40,7 @@ int do_yumount (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) return(0); } -int do_yls (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +int do_yls (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { char *dirname = argv[argc-1]; @@ -49,7 +49,7 @@ int do_yls (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) return(0); } -int do_yrd (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +int do_yrd (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { char *filename = argv[1]; printf ("Reading file %s ", filename); @@ -60,7 +60,7 @@ int do_yrd (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) return(0); } -int do_ywr (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +int do_ywr (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { char *filename = argv[1]; ulong value = simple_strtoul(argv[2], NULL, 16); @@ -74,7 +74,7 @@ int do_ywr (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) return(0); } -int do_yrdm (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +int do_yrdm (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { char *filename = argv[1]; ulong addr = simple_strtoul(argv[2], NULL, 16); @@ -84,7 +84,7 @@ int do_yrdm (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) return(0); } -int do_ywrm (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +int do_ywrm (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { char *filename = argv[1]; ulong addr = simple_strtoul(argv[2], NULL, 16); @@ -95,7 +95,7 @@ int do_ywrm (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) return(0); } -int do_ymkdir (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +int do_ymkdir (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { char *dirname = argv[1]; @@ -104,7 +104,7 @@ int do_ymkdir (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) return(0); } -int do_yrmdir (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +int do_yrmdir (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { char *dirname = argv[1]; @@ -113,7 +113,7 @@ int do_yrmdir (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) return(0); } -int do_yrm (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +int do_yrm (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { char *path = argv[1]; @@ -122,7 +122,7 @@ int do_yrm (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) return(0); } -int do_ymv (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +int do_ymv (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { char *oldPath = argv[1]; char *newPath = argv[2]; @@ -132,7 +132,7 @@ int do_ymv (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) return(0); } -int do_ydump (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +int do_ydump (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { char *dirname = argv[1]; if (yaffs_DumpDevStruct(dirname) != 0) -- cgit v1.2.3-70-g09d2