Hello Rusty Russell: please help to review this patch whether is OK, when you have time.
thanks. gchen. On 2013年04月11日 13:32, Chen Gang wrote: > > We don't export any symbols > 128 characters, but if we did then > kallsyms_expand_symbol() would overflow the buffer handed to it. > So we need check destination buffer length when copying. > > the related test: > if we define an EXPORT function which name more than 128. > will panic when call kallsyms_lookup_name by init_kprobes on booting. > after check the length (provide this patch), it is ok. > > Implementaion: > add additional destination buffer length parameter (maxlen) > if uncompressed string is too long (>= maxlen), it will be truncated. > not check the parameters whether valid, since it is a static function. > > > Signed-off-by: Chen Gang <[email protected]> > --- > kernel/kallsyms.c | 26 ++++++++++++++++++-------- > 1 files changed, 18 insertions(+), 8 deletions(-) > > diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c > index 2169fee..43d8150 100644 > --- a/kernel/kallsyms.c > +++ b/kernel/kallsyms.c > @@ -84,9 +84,11 @@ static int is_ksym_addr(unsigned long addr) > > /* > * Expand a compressed symbol data into the resulting uncompressed string, > + * if uncompressed string is too long (>= maxlen), it will be truncated, > * given the offset to where the symbol is in the compressed stream. > */ > -static unsigned int kallsyms_expand_symbol(unsigned int off, char *result) > +static unsigned int kallsyms_expand_symbol(unsigned int off, > + char *result, size_t maxlen) > { > int len, skipped_first = 0; > const u8 *tptr, *data; > @@ -113,15 +115,20 @@ static unsigned int kallsyms_expand_symbol(unsigned int > off, char *result) > > while (*tptr) { > if (skipped_first) { > + if (maxlen <= 1) > + goto tail; > *result = *tptr; > result++; > + maxlen--; > } else > skipped_first = 1; > tptr++; > } > } > > - *result = '\0'; > +tail: > + if (maxlen) > + *result = '\0'; > > /* Return to offset to the next symbol. */ > return off; > @@ -176,7 +183,7 @@ unsigned long kallsyms_lookup_name(const char *name) > unsigned int off; > > for (i = 0, off = 0; i < kallsyms_num_syms; i++) { > - off = kallsyms_expand_symbol(off, namebuf); > + off = kallsyms_expand_symbol(off, namebuf, ARRAY_SIZE(namebuf)); > > if (strcmp(namebuf, name) == 0) > return kallsyms_addresses[i]; > @@ -195,7 +202,7 @@ int kallsyms_on_each_symbol(int (*fn)(void *, const char > *, struct module *, > int ret; > > for (i = 0, off = 0; i < kallsyms_num_syms; i++) { > - off = kallsyms_expand_symbol(off, namebuf); > + off = kallsyms_expand_symbol(off, namebuf, ARRAY_SIZE(namebuf)); > ret = fn(data, namebuf, NULL, kallsyms_addresses[i]); > if (ret != 0) > return ret; > @@ -294,7 +301,8 @@ const char *kallsyms_lookup(unsigned long addr, > > pos = get_symbol_pos(addr, symbolsize, offset); > /* Grab name */ > - kallsyms_expand_symbol(get_symbol_offset(pos), namebuf); > + kallsyms_expand_symbol(get_symbol_offset(pos), > + namebuf, ARRAY_SIZE(namebuf)); > if (modname) > *modname = NULL; > return namebuf; > @@ -315,7 +323,8 @@ int lookup_symbol_name(unsigned long addr, char *symname) > > pos = get_symbol_pos(addr, NULL, NULL); > /* Grab name */ > - kallsyms_expand_symbol(get_symbol_offset(pos), symname); > + kallsyms_expand_symbol(get_symbol_offset(pos), > + symname, ARRAY_SIZE(symname)); > return 0; > } > /* See if it's in a module. */ > @@ -333,7 +342,8 @@ int lookup_symbol_attrs(unsigned long addr, unsigned long > *size, > > pos = get_symbol_pos(addr, size, offset); > /* Grab name */ > - kallsyms_expand_symbol(get_symbol_offset(pos), name); > + kallsyms_expand_symbol(get_symbol_offset(pos), > + name, ARRAY_SIZE(name)); > modname[0] = '\0'; > return 0; > } > @@ -463,7 +473,7 @@ static unsigned long get_ksymbol_core(struct kallsym_iter > *iter) > > iter->type = kallsyms_get_symbol_type(off); > > - off = kallsyms_expand_symbol(off, iter->name); > + off = kallsyms_expand_symbol(off, iter->name, ARRAY_SIZE(iter->name)); > > return off - iter->nameoff; > } > -- Chen Gang Asianux Corporation -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
