bpf: Use safer kvmalloc_array() where possible

The kvmalloc_array() function is safer because it has a check for
integer overflows.  These sizes come from the user and I was not
able to see any bounds checking so an integer overflow seems like a
realistic concern.

Fixes: 0dcac2725406 ("bpf: Add multi kprobe link")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/Yo9VRVMeHbALyjUH@kili
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 10b157a6d73e0746d3ae2bf5ccfcd3423384085f..7a13e6ac6327ced0adedd309a1895a947572f1f7 100644 (file)
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -2263,11 +2263,11 @@ static int copy_user_syms(struct user_syms *us, unsigned long __user *usyms, u32
        int err = -ENOMEM;
        unsigned int i;
 
-       syms = kvmalloc(cnt * sizeof(*syms), GFP_KERNEL);
+       syms = kvmalloc_array(cnt, sizeof(*syms), GFP_KERNEL);
        if (!syms)
                goto error;
 
-       buf = kvmalloc(cnt * KSYM_NAME_LEN, GFP_KERNEL);
+       buf = kvmalloc_array(cnt, KSYM_NAME_LEN, GFP_KERNEL);
        if (!buf)
                goto error;
 
@@ -2464,7 +2464,7 @@ int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr
                return -EINVAL;
 
        size = cnt * sizeof(*addrs);
-       addrs = kvmalloc(size, GFP_KERNEL);
+       addrs = kvmalloc_array(cnt, sizeof(*addrs), GFP_KERNEL);
        if (!addrs)
                return -ENOMEM;
 
@@ -2489,7 +2489,7 @@ int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr
 
        ucookies = u64_to_user_ptr(attr->link_create.kprobe_multi.cookies);
        if (ucookies) {
-               cookies = kvmalloc(size, GFP_KERNEL);
+               cookies = kvmalloc_array(cnt, sizeof(*addrs), GFP_KERNEL);
                if (!cookies) {
                        err = -ENOMEM;
                        goto error;