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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_bedbug.c
parentb218ccb5435e64ac2318bb8b6c9594ef1cc724cd (diff)
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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_bedbug.c')
-rw-r--r--common/cmd_bedbug.c16
1 files changed, 8 insertions, 8 deletions
diff --git a/common/cmd_bedbug.c b/common/cmd_bedbug.c
index 8be1c25..d01ee19 100644
--- a/common/cmd_bedbug.c
+++ b/common/cmd_bedbug.c
@@ -73,7 +73,7 @@ void bedbug_init (void)
* Entry point from the interpreter to the disassembler. Repeated calls
* will resume from the last disassembled address.
* ====================================================================== */
-int do_bedbug_dis (cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
+int do_bedbug_dis (cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
{
ulong addr; /* Address to start disassembly from */
ulong len; /* # of instructions to disassemble */
@@ -115,7 +115,7 @@ U_BOOT_CMD (ds, 3, 1, do_bedbug_dis,
* instructions in consecutive memory locations until a '.' (period) is
* entered on a line by itself.
* ====================================================================== */
-int do_bedbug_asm (cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
+int do_bedbug_asm (cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
{
long mem_addr; /* Address to assemble into */
unsigned long instr; /* Machine code for text */
@@ -167,7 +167,7 @@ U_BOOT_CMD (as, 2, 0, do_bedbug_asm,
* CPU-specific break point set routine.
* ====================================================================== */
-int do_bedbug_break (cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
+int do_bedbug_break (cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
{
/* -------------------------------------------------- */
if (bug_ctx.do_break)
@@ -263,7 +263,7 @@ void bedbug_main_loop (unsigned long addr, struct pt_regs *regs)
* stopped flag in the context so that the breakpoint routine will
* return.
* ====================================================================== */
-int do_bedbug_continue (cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
+int do_bedbug_continue (cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
{
/* -------------------------------------------------- */
@@ -286,7 +286,7 @@ U_BOOT_CMD (continue, 1, 0, do_bedbug_continue,
* the address passes control to the CPU-specific set breakpoint routine
* for the current breakpoint number.
* ====================================================================== */
-int do_bedbug_step (cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
+int do_bedbug_step (cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
{
unsigned long addr; /* Address to stop at */
@@ -317,7 +317,7 @@ U_BOOT_CMD (step, 1, 1, do_bedbug_step,
* the address passes control to the CPU-specific set breakpoint routine
* for the current breakpoint number.
* ====================================================================== */
-int do_bedbug_next (cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
+int do_bedbug_next (cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
{
unsigned long addr; /* Address to stop at */
@@ -346,7 +346,7 @@ U_BOOT_CMD (next, 1, 1, do_bedbug_next,
* Interpreter command to print the current stack. This assumes an EABI
* architecture, so it starts with GPR R1 and works back up the stack.
* ====================================================================== */
-int do_bedbug_stack (cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
+int do_bedbug_stack (cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
{
unsigned long sp; /* Stack pointer */
unsigned long func; /* LR from stack */
@@ -391,7 +391,7 @@ U_BOOT_CMD (where, 1, 1, do_bedbug_stack,
* Interpreter command to dump the registers. Calls the CPU-specific
* show registers routine.
* ====================================================================== */
-int do_bedbug_rdump (cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
+int do_bedbug_rdump (cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
{
/* -------------------------------------------------- */