2 files changed, 15 insertions, 3 deletions

diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index c41fa2af7677..e3ff2b9e602f 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -152,8 +152,10 @@ create_elf_tables(struct linux_binprm *bprm, struct elfhdr *exec,
         elf_addr_t __user *sp;
         elf_addr_t __user *u_platform;
         elf_addr_t __user *u_base_platform;
+        elf_addr_t __user *u_rand_bytes;
         const char *k_platform = ELF_PLATFORM;
         const char *k_base_platform = ELF_BASE_PLATFORM;
+        unsigned char k_rand_bytes[16];
         int items;
         elf_addr_t *elf_info;
         int ei_index = 0;
@@ -196,6 +198,15 @@ create_elf_tables(struct linux_binprm *bprm, struct elfhdr *exec,
                         return -EFAULT;
         }
 
+        /*
+         * Generate 16 random bytes for userspace PRNG seeding.
+         */
+        get_random_bytes(k_rand_bytes, sizeof(k_rand_bytes));
+        u_rand_bytes = (elf_addr_t __user *)
+                       STACK_ALLOC(p, sizeof(k_rand_bytes));
+        if (__copy_to_user(u_rand_bytes, k_rand_bytes, sizeof(k_rand_bytes)))
+                return -EFAULT;
+
         /* Create the ELF interpreter info */
         elf_info = (elf_addr_t *)current->mm->saved_auxv;
         /* update AT_VECTOR_SIZE_BASE if the number of NEW_AUX_ENT() changes */
@@ -228,6 +239,7 @@ create_elf_tables(struct linux_binprm *bprm, struct elfhdr *exec,
         NEW_AUX_ENT(AT_GID, cred->gid);
         NEW_AUX_ENT(AT_EGID, cred->egid);
         NEW_AUX_ENT(AT_SECURE, security_bprm_secureexec(bprm));
+        NEW_AUX_ENT(AT_RANDOM, (elf_addr_t)(unsigned long)u_rand_bytes);
         NEW_AUX_ENT(AT_EXECFN, bprm->exec);
         if (k_platform) {
                 NEW_AUX_ENT(AT_PLATFORM,
diff --git a/include/linux/auxvec.h b/include/linux/auxvec.h
index d7afa9dd6635..f3b5d4e3a2ac 100644
--- a/include/linux/auxvec.h
+++ b/include/linux/auxvec.h
@@ -23,16 +23,16 @@
 #define AT_PLATFORM 15  /* string identifying CPU for optimizations */
 #define AT_HWCAP  16    /* arch dependent hints at CPU capabilities */
 #define AT_CLKTCK 17    /* frequency at which times() increments */
-
+/* AT_* values 18 through 22 are reserved */
 #define AT_SECURE 23   /* secure mode boolean */
-
 #define AT_BASE_PLATFORM 24     /* string identifying real platform, may
                                  * differ from AT_PLATFORM. */
+#define AT_RANDOM 25    /* address of 16 random bytes */
 
 #define AT_EXECFN  31   /* filename of program */
 
 #ifdef __KERNEL__
-#define AT_VECTOR_SIZE_BASE 18 /* NEW_AUX_ENT entries in auxiliary table */
+#define AT_VECTOR_SIZE_BASE 19 /* NEW_AUX_ENT entries in auxiliary table */
   /* number of "#define AT_.*" above, minus {AT_NULL, AT_IGNORE, AT_NOTELF} */
 #endif