Fixes for potential deadlock

Fixes (#24517):
(3/3) Addresses the potential deadlock if an error occurs from up_ref
in functions ENGINE_get_first, ENGINE_get_last, ENGINE_get_next, and
ENGINE_get_prev in file crypto/engine/eng_list.c

CLA: trivial

Reviewed-by: Neil Horman <nhorman@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/24780)

(cherry picked from commit e6174ca4d48f6f4f954dd87f2cdf3718af14f064)

diff --git a/crypto/engine/eng_list.c b/crypto/engine/eng_list.c
index a2c151d64a04ae13ee492fc32c429b4b5ae83bda..eafca3ec49ce85ba1c8c1431f648df76a369d64a 100644 (file)
--- a/crypto/engine/eng_list.c
+++ b/crypto/engine/eng_list.c
@@ -243,6 +243,7 @@ ENGINE *ENGINE_get_first(void)
         int ref;
 
         if (!CRYPTO_UP_REF(&ret->struct_ref, &ref)) {
+            CRYPTO_THREAD_unlock(global_engine_lock);
             ERR_raise(ERR_LIB_ENGINE, ERR_R_CRYPTO_LIB);
             return NULL;
         }
@@ -269,6 +270,7 @@ ENGINE *ENGINE_get_last(void)
         int ref;
 
         if (!CRYPTO_UP_REF(&ret->struct_ref, &ref)) {
+            CRYPTO_THREAD_unlock(global_engine_lock);
             ERR_raise(ERR_LIB_ENGINE, ERR_R_CRYPTO_LIB);
             return NULL;
         }
@@ -294,6 +296,7 @@ ENGINE *ENGINE_get_next(ENGINE *e)
 
         /* Return a valid structural reference to the next ENGINE */
         if (!CRYPTO_UP_REF(&ret->struct_ref, &ref)) {
+            CRYPTO_THREAD_unlock(global_engine_lock);
             ERR_raise(ERR_LIB_ENGINE, ERR_R_CRYPTO_LIB);
             return NULL;
         }
@@ -320,6 +323,7 @@ ENGINE *ENGINE_get_prev(ENGINE *e)
 
         /* Return a valid structural reference to the next ENGINE */
         if (!CRYPTO_UP_REF(&ret->struct_ref, &ref)) {
+            CRYPTO_THREAD_unlock(global_engine_lock);
             ERR_raise(ERR_LIB_ENGINE, ERR_R_CRYPTO_LIB);
             return NULL;
         }