All of this logic was simplified back in '05 in the BSD drivers by adding
this to the top of the function:
u_int dummy_column;
if (cur_column == NULL) {
dummy_column = 0;
cur_column = &dummy_column;
}
and then stripping out the cur_column == NULL checks in the routine.
--
Justin
Jesper Juhl wrote:
On 04/08/07, James Bottomley <[email protected]> wrote:
On Sat, 2007-08-04 at 20:30 +0200, Jesper Juhl wrote:
(resend of patch previously submitted on 28-Jul-2007 23:06)
Ehlo,
The Coverity checker noticed that we have a potential NULL pointer
deref in drivers/scsi/aic7xxx/aic7xxx_core.c::ahc_print_register().
This patch handles it by adding the same test against NULL that is
used elsewhere in the same function.
It's on my list of things to look at ... but not very high. I suspect
it actually isn't triggerable, but if you can tell me how, it will save
me from looking.
Here's what Coverity reported :
...
6525 int
6526 ahc_print_register(ahc_reg_parse_entry_t *table, u_int num_entries,
6527 const char *name, u_int address, u_int value,
6528 u_int *cur_column, u_int wrap_point)
6529 {
6530 int printed;
6531 u_int printed_mask;
6532
Event var_compare_op: Added "cur_column" due to comparison "cur_column != 0"
Also see events: [var_deref_op]
At conditional (1): "cur_column != 0" taking false path
6533 if (cur_column != NULL && *cur_column >= wrap_point) {
6534 printf("\n");
6535 *cur_column = 0;
6536 }
6537 printed = printf("%s[0x%x]", name, value);
At conditional (2): "table == 0" taking true path
6538 if (table == NULL) {
6539 printed += printf(" ");
Event var_deref_op: Variable "cur_column" tracked as NULL was dereferenced.
Also see events: [var_compare_op]
6540 *cur_column += printed;
6541 return (printed);
6542 }
...
So it requires a NULL 'table' and a != NULL 'cur_column' to trigger.
Whether or not that's actually possible I'm not sure, but it seems
safer to guard against it :)
By the way; if this can actually be triggered, then
ahd_print_register() has the same problem.
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