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authorChen Gang <gang.chen@asianux.com>2013-04-15 15:04:43 +0930
committerRusty Russell <rusty@rustcorp.com.au>2013-04-15 15:17:26 +0930
commite3f26752f0f8a6aade580115e1e68bcb1a4bc040 (patch)
tree04e818066d7d0faa64abfe55b4841da984f3812f
parent07c449bbc6aa514098c4f12c7b04180cec2417c6 (diff)
downloadop-kernel-dev-e3f26752f0f8a6aade580115e1e68bcb1a4bc040.zip
op-kernel-dev-e3f26752f0f8a6aade580115e1e68bcb1a4bc040.tar.gz
kernel: kallsyms: memory override issue, need check destination buffer length
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.chen@asianux.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
-rw-r--r--kernel/kallsyms.c26
1 files changed, 18 insertions, 8 deletions
diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c
index 2169fee..3127ad5 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, KSYM_NAME_LEN);
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, KSYM_NAME_LEN);
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, KSYM_NAME_LEN);
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;
}
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