Messages in this thread | | | Date | Wed, 23 Jan 2008 18:26:28 +0000 | From | Paulo Marques <> | Subject | Re: [PATCH 1/6] POWERPC: use KSYM_NAME_LEN |
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Cyrill Gorcunov wrote: > Use KSYM_NAME_LEN instead of numeric value.
The patch series looks like a nice cleanup, except for a few things in this patch.
> Actually because of too small 'tmp' there is > a potential buffer overflow.
I don't think there is. "tmp" is not being passed to kallsyms to be filled with a symbol name, but it's being used to hold a name written by the user to lookup an address.
If the powerpc/xmon people feel that 63 characters is enough to hold a symbol name, it's their problem, but there is no buffer overflow.
> Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com> > --- > > Index: linux-2.6.git/arch/powerpc/xmon/xmon.c > =================================================================== > --- linux-2.6.git.orig/arch/powerpc/xmon/xmon.c 2008-01-23 19:04:42.000000000 +0300 > +++ linux-2.6.git/arch/powerpc/xmon/xmon.c 2008-01-23 19:12:45.000000000 +0300 > @@ -69,7 +69,7 @@ static unsigned long ndump = 64; > static unsigned long nidump = 16; > static unsigned long ncsum = 4096; > static int termch; > -static char tmpstr[128]; > +static char tmpstr[KSYM_NAME_LEN];
This one seems ok, since "tmpstr" is used everywhere to hold symbol names.
> #define JMP_BUF_LEN 23 > static long bus_error_jmp[JMP_BUF_LEN]; > @@ -2354,7 +2354,7 @@ scanhex(unsigned long *vp) > } > } else if (c == '$') { > int i; > - for (i=0; i<63; i++) { > + for (i = 0; i < sizeof(tmpstr) / 2; i++) {
This one is completely out of the blue. Why "sizeof(tmpstr) / 2"?
It would make more sense to use "sizeof(tmpstr) - 1", but either way it is a change in behavior.
> c = inchar(); > if (isspace(c)) { > termch = c; > @@ -2467,7 +2467,7 @@ symbol_lookup(void) > { > int type = inchar(); > unsigned long addr; > - static char tmp[64]; > + static char tmp[KSYM_NAME_LEN]; > > switch (type) { > case 'a': > @@ -2476,7 +2476,7 @@ symbol_lookup(void) > termch = 0; > break; > case 's': > - getstring(tmp, 64); > + getstring(tmp, sizeof(tmp)); > if (setjmp(bus_error_jmp) == 0) { > catch_memory_errors = 1; > sync();
This also introduces a change in behavior. It is still a nice cleanup, though. So, if the powerpc people feel they can spare an extra 64 bytes of stack here, I guess it's ok.
-- Paulo Marques - www.grupopie.com
"As far as we know, our computer has never had an undetected error." Weisert
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