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 <gang.c...@asianux.com>
Signed-off-by: Rusty Russell <ru...@rustcorp.com.au>
---
kernel/kallsyms.c | 26 +++++++++++++++++---------
1 files changed, 17 insertions(+), 9 deletions(-)
diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c
index 2169fee..ae7b90d 100644
--- a/kernel/kallsyms.c
+++ b/kernel/kallsyms.c
@@ -84,12 +84,15 @@ 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, int maxlen)
{
int len, skipped_first = 0;
const u8 *tptr, *data;
+ char *begin = result;
/* Get the compressed symbol length from the first symbol byte. */
data = &kallsyms_names[off];
@@ -113,14 +116,16 @@ static unsigned int kallsyms_expand_symbol(unsigned int
off, char *result)
while (*tptr) {
if (skipped_first) {
- *result = *tptr;
- result++;
+ *result++ = *tptr;
+ if (result - begin == maxlen - 1)
+ goto tail;
} else
skipped_first = 1;
tptr++;
}
}
+tail:
*result = '\0';
/* Return to offset to the next symbol. */
@@ -176,7 +181,7 @@ 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, sizeof(namebuf));
if (strcmp(namebuf, name) == 0)
return kallsyms_addresses[i];
@@ -195,7 +200,7 @@ 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, sizeof(namebuf));
ret = fn(data, namebuf, NULL, kallsyms_addresses[i]);
if (ret != 0)
return ret;
@@ -294,7 +299,8 @@ 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, sizeof(namebuf));
if (modname)
*modname = NULL;
return namebuf;
@@ -315,7 +321,8 @@ 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, sizeof(symname));
return 0;
}
/* See if it's in a module. */
@@ -333,7 +340,8 @@ 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, sizeof(name));
modname[0] = '\0';
return 0;
}
@@ -463,7 +471,7 @@ 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, sizeof(iter->name));
return off - iter->nameoff;
}
--
1.7.7.6
--
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