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linuxkm/lkcapi_sha_glue.c: in wc_linuxkm_drbg_startup(), deinstall the callbacks and stdrng first before checking refcnt.

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This commit is contained in:
Daniel Pouzzner
2025-12-26 16:41:43 -06:00
parent 3b3ddd1fb4
commit 283792c207
1 changed files with 17 additions and 24 deletions
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41
linuxkm/lkcapi_sha_glue.c
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@@ -2150,25 +2150,18 @@ static int wc_linuxkm_drbg_startup(void)
}
static int wc_linuxkm_drbg_cleanup(void) {
int cur_refcnt = WC_LKM_REFCOUNT_TO_INT(wc_linuxkm_drbg.base.cra_refcnt);
int cur_refcnt;
if (! wc_linuxkm_drbg_loaded) {
pr_err("ERROR: wc_linuxkm_drbg_cleanup called with ! wc_linuxkm_drbg_loaded");
return -EINVAL;
}
if (cur_refcnt - wc_linuxkm_drbg_default_instance_registered != 1) {
pr_err("ERROR: wc_linuxkm_drbg_cleanup called with refcnt = %d, with wc_linuxkm_drbg %sset as default rng",
cur_refcnt, wc_linuxkm_drbg_default_instance_registered ? "" : "not ");
return -EBUSY;
}
/* The below is racey, but the kernel doesn't provide any other way. It's
* written to be retryable.
*/
#ifdef LINUXKM_LKCAPI_REGISTER_HASH_DRBG_DEFAULT
if (wc_linuxkm_drbg_default_instance_registered) {
/* These deinstallations are racey, but the kernel doesn't provide any other
* way. It's written to be retryable.
*/
int ret;
#ifdef LINUXKM_DRBG_GET_RANDOM_BYTES
@@ -2193,16 +2186,16 @@ static int wc_linuxkm_drbg_cleanup(void) {
#elif defined(WOLFSSL_LINUXKM_USE_GET_RANDOM_KPROBES)
if (wc_get_random_bytes_kprobe_installed) {
wc_get_random_bytes_kprobe_installed = 0;
barrier();
unregister_kprobe(&wc_get_random_bytes_kprobe);
barrier();
wc_get_random_bytes_kprobe_installed = 0;
pr_info("libwolfssl: wc_get_random_bytes_kprobe uninstalled\n");
}
#ifdef WOLFSSL_LINUXKM_USE_GET_RANDOM_USER_KRETPROBE
if (wc_get_random_bytes_user_kretprobe_installed) {
wc_get_random_bytes_user_kretprobe_installed = 0;
barrier();
unregister_kretprobe(&wc_get_random_bytes_user_kretprobe);
barrier();
wc_get_random_bytes_user_kretprobe_installed = 0;
pr_info("libwolfssl: wc_get_random_bytes_user_kretprobe uninstalled\n");
}
#endif /* WOLFSSL_LINUXKM_USE_GET_RANDOM_USER_KRETPROBE */
@@ -2218,14 +2211,18 @@ static int wc_linuxkm_drbg_cleanup(void) {
pr_err("ERROR: crypto_del_default_rng failed: %d", ret);
return ret;
}
cur_refcnt = WC_LKM_REFCOUNT_TO_INT(wc_linuxkm_drbg.base.cra_refcnt);
if (cur_refcnt != 1) {
pr_warn("WARNING: wc_linuxkm_drbg refcnt = %d after crypto_del_default_rng()", cur_refcnt);
return -EINVAL;
}
wc_linuxkm_drbg_default_instance_registered = 0;
}
#endif /* LINUXKM_LKCAPI_REGISTER_HASH_DRBG_DEFAULT */
cur_refcnt = WC_LKM_REFCOUNT_TO_INT(wc_linuxkm_drbg.base.cra_refcnt);
if (cur_refcnt != 1) {
pr_err("ERROR: wc_linuxkm_drbg_cleanup called with refcnt = %d", cur_refcnt);
return -EBUSY;
}
crypto_unregister_rng(&wc_linuxkm_drbg);
if (! (wc_linuxkm_drbg.base.cra_flags & CRYPTO_ALG_DEAD)) {
@@ -2233,10 +2230,6 @@ static int wc_linuxkm_drbg_cleanup(void) {
return -EBUSY;
}
#ifdef LINUXKM_LKCAPI_REGISTER_HASH_DRBG_DEFAULT
wc_linuxkm_drbg_default_instance_registered = 0;
#endif /* LINUXKM_LKCAPI_REGISTER_HASH_DRBG_DEFAULT */
wc_linuxkm_drbg_loaded = 0;
return 0;