@@ -2352,12 +2352,15 @@ static int
kprobe_multi_resolve_syms(const void __user *usyms, u32 cnt,
unsigned long *addrs)
{
- unsigned long addr, size;
+ unsigned long addr, sym_size;
+ u32 size;
const char __user **syms;
int err = -ENOMEM;
unsigned int i;
char *func;
+ if (check_mul_overflow(cnt, (u32)sizeof(*syms), &size))
+ return -EOVERFLOW;
size = cnt * sizeof(*syms);
syms = kvzalloc(size, GFP_KERNEL);
if (!syms)
@@ -2382,9 +2385,9 @@ kprobe_multi_resolve_syms(const void __user *usyms, u32 cnt,
addr = kallsyms_lookup_name(func);
if (!addr)
goto error;
- if (!kallsyms_lookup_size_offset(addr, &size, NULL))
+ if (!kallsyms_lookup_size_offset(addr, &sym_size, NULL))
goto error;
- addr = ftrace_location_range(addr, addr + size - 1);
+ addr = ftrace_location_range(addr, addr + sym_size - 1);
if (!addr)
goto error;
addrs[i] = addr;
@@ -2429,6 +2432,8 @@ int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr
if (!cnt)
return -EINVAL;
+ if (check_mul_overflow(cnt, (u32)sizeof(*addrs), &size))
+ return -EOVERFLOW;
size = cnt * sizeof(*addrs);
addrs = kvmalloc(size, GFP_KERNEL);
if (!addrs)
Check that size would not overflow before calculation (and return -EOVERFLOW if it will), to prevent potential out-of-bounds write with the following copy_from_user. Add the same check to kprobe_multi_resolve_syms in case it will be called from elsewhere in the future. Fixes: 0dcac272540613d4 ("bpf: Add multi kprobe link") Signed-off-by: Eugene Syromiatnikov <esyr@redhat.com> --- kernel/trace/bpf_trace.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-)