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 --- arch/powerpc/cpu/mpc512x/cpu.c | 2 +- arch/powerpc/cpu/mpc512x/diu.c | 2 +- arch/powerpc/cpu/mpc512x/iim.c | 2 +- arch/powerpc/cpu/mpc512x/speed.c | 2 +- 4 files changed, 4 insertions(+), 4 deletions(-) (limited to 'arch/powerpc/cpu/mpc512x') diff --git a/arch/powerpc/cpu/mpc512x/cpu.c b/arch/powerpc/cpu/mpc512x/cpu.c index 09cbd2024d..a1a3bd4adf 100644 --- a/arch/powerpc/cpu/mpc512x/cpu.c +++ b/arch/powerpc/cpu/mpc512x/cpu.c @@ -75,7 +75,7 @@ int checkcpu (void) int -do_reset (cmd_tbl_t * cmdtp, int flag, int argc, char *argv[]) +do_reset (cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[]) { ulong msr; volatile immap_t *immap = (immap_t *) CONFIG_SYS_IMMR; diff --git a/arch/powerpc/cpu/mpc512x/diu.c b/arch/powerpc/cpu/mpc512x/diu.c index 1cce6a233c..f638c00372 100644 --- a/arch/powerpc/cpu/mpc512x/diu.c +++ b/arch/powerpc/cpu/mpc512x/diu.c @@ -107,7 +107,7 @@ int mpc5121_diu_init(void) } int mpc5121diu_init_show_bmp(cmd_tbl_t *cmdtp, - int flag, int argc, char *argv[]) + int flag, int argc, char * const argv[]) { unsigned int addr; diff --git a/arch/powerpc/cpu/mpc512x/iim.c b/arch/powerpc/cpu/mpc512x/iim.c index 8f2eb37e17..abec8f61cc 100644 --- a/arch/powerpc/cpu/mpc512x/iim.c +++ b/arch/powerpc/cpu/mpc512x/iim.c @@ -278,7 +278,7 @@ int ads5121_fuse_stat(int bank) return 0; } -int do_ads5121_fuse(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +int do_ads5121_fuse(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { int frow, n, v, bank; diff --git a/arch/powerpc/cpu/mpc512x/speed.c b/arch/powerpc/cpu/mpc512x/speed.c index ce8d0949b2..9d749f22e4 100644 --- a/arch/powerpc/cpu/mpc512x/speed.c +++ b/arch/powerpc/cpu/mpc512x/speed.c @@ -131,7 +131,7 @@ ulong get_bus_freq (ulong dummy) return gd->csb_clk; } -int do_clocks (cmd_tbl_t * cmdtp, int flag, int argc, char *argv[]) +int do_clocks (cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[]) { char buf[32]; -- cgit v1.2.1