linux-kernel - [PATCH] fs/binfmt_elf: Fix memleak in load_elf

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Date:   Thu, 27 Aug 2020 19:46:39 +0800
From:   Dinghao Liu <dinghao.liu@....edu.cn>
To:     dinghao.liu@....edu.cn, kjlu@....edu
Cc:     Alexander Viro <viro@...iv.linux.org.uk>,
        linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH] fs/binfmt_elf: Fix memleak in load_elf_binary

When arch_setup_additional_pages() fails, interp_elf_ex may
not have been freed, which leads to memleak.  It's the same
when create_elf_tables() fails.

Signed-off-by: Dinghao Liu <dinghao.liu@....edu.cn>
---
 fs/binfmt_elf.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 13d053982dd7..984c30684e49 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -1204,6 +1204,7 @@ static int load_elf_binary(struct linux_binprm *bprm)
 		fput(interpreter);
 
 		kfree(interp_elf_ex);
+		interp_elf_ex = NULL;
 		kfree(interp_elf_phdata);
 	} else {
 		elf_entry = e_entry;
@@ -1219,14 +1220,18 @@ static int load_elf_binary(struct linux_binprm *bprm)
 
 #ifdef ARCH_HAS_SETUP_ADDITIONAL_PAGES
 	retval = arch_setup_additional_pages(bprm, !!interpreter);
-	if (retval < 0)
+	if (retval < 0) {
+		kfree(interp_elf_ex);
 		goto out;
+	}
 #endif /* ARCH_HAS_SETUP_ADDITIONAL_PAGES */
 
 	retval = create_elf_tables(bprm, elf_ex,
 			  load_addr, interp_load_addr, e_entry);
-	if (retval < 0)
+	if (retval < 0) {
+		kfree(interp_elf_ex);
 		goto out;
+	}
 
 	mm = current->mm;
 	mm->end_code = end_code;
-- 
2.17.1