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 --- board/esd/tasreg/tasreg.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) (limited to 'board/esd/tasreg/tasreg.c') diff --git a/board/esd/tasreg/tasreg.c b/board/esd/tasreg/tasreg.c index bd9fb2fc2b..270caac08c 100644 --- a/board/esd/tasreg/tasreg.c +++ b/board/esd/tasreg/tasreg.c @@ -29,7 +29,7 @@ /* Prototypes */ -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[]); int i2c_write(uchar chip, uint addr, int alen, uchar *buffer, int len); int i2c_read(uchar chip, uint addr, int alen, uchar *buffer, int len); @@ -219,7 +219,7 @@ int i2c_probe(uchar addr); /* */ -int do_iploop(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +int do_iploop(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { ulong addr; @@ -254,7 +254,7 @@ U_BOOT_CMD( /* */ -int do_codec(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +int do_codec(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { uchar buf[8]; @@ -307,7 +307,7 @@ U_BOOT_CMD( /* */ -int do_saa(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +int do_saa(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { ulong addr; ulong instr; @@ -340,7 +340,7 @@ U_BOOT_CMD( /* */ -int do_iwrite(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +int do_iwrite(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { ulong addr; ulong data0; @@ -379,7 +379,7 @@ U_BOOT_CMD( /* */ -int do_iread(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +int do_iread(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { ulong addr; ulong cnt; @@ -411,7 +411,7 @@ U_BOOT_CMD( /* */ -int do_ireadl(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +int do_ireadl(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { ulong addr; uchar buf[32]; -- cgit