linux-kernel - [PATCH v3 1/3] tools/bootconfig: Fix to check the write failure correctly

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <160560677952.144950.8229834525319742454.stgit@devnote2>
Date:   Tue, 17 Nov 2020 18:52:59 +0900
From:   Masami Hiramatsu <mhiramat@...nel.org>
To:     Steven Rostedt <rostedt@...dmis.org>,
        Linus Torvalds <torvalds@...ux-foundation.org>
Cc:     Chen Yu <yu.c.chen@...el.com>, Chen Yu <yu.chen.surf@...il.com>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Ingo Molnar <mingo@...nel.org>,
        Jonathan Corbet <corbet@....net>
Subject: [PATCH v3 1/3] tools/bootconfig: Fix to check the write failure correctly

Fix to check the write(2) failure including partial write
correctly and try to rollback the partial write, because
if there is no BOOTCONFIG_MAGIC string, we can not remove it.

Fixes: 85c46b78da58 ("bootconfig: Add bootconfig magic word for indicating bootconfig explicitly")
Suggested-by: Linus Torvalds <torvalds@...ux-foundation.org>
Signed-off-by: Masami Hiramatsu <mhiramat@...nel.org>
---
 tools/bootconfig/main.c |   27 +++++++++++++++++++++++----
 1 file changed, 23 insertions(+), 4 deletions(-)

diff --git a/tools/bootconfig/main.c b/tools/bootconfig/main.c
index eb92027817a7..f7b89a50404c 100644
--- a/tools/bootconfig/main.c
+++ b/tools/bootconfig/main.c
@@ -332,6 +332,7 @@ static int delete_xbc(const char *path)
 
 static int apply_xbc(const char *path, const char *xbc_path)
 {
+	struct stat stat;
 	u32 size, csum;
 	char *buf, *data;
 	int ret, fd;
@@ -388,16 +389,26 @@ static int apply_xbc(const char *path, const char *xbc_path)
 		return fd;
 	}
 	/* TODO: Ensure the @path is initramfs/initrd image */
+	if (fstat(fd, &stat) < 0) {
+		pr_err("Failed to get the size of %s\n", path);
+		goto out;
+	}
 	ret = write(fd, data, size + 8);
-	if (ret < 0) {
+	if (ret < size + 8) {
+		if (ret < 0)
+			ret = -errno;
 		pr_err("Failed to apply a boot config: %d\n", ret);
-		goto out;
+		if (ret < 0)
+			goto out;
+		goto out_rollback;
 	}
 	/* Write a magic word of the bootconfig */
 	ret = write(fd, BOOTCONFIG_MAGIC, BOOTCONFIG_MAGIC_LEN);
-	if (ret < 0) {
+	if (ret < BOOTCONFIG_MAGIC_LEN) {
+		if (ret < 0)
+			ret = -errno;
 		pr_err("Failed to apply a boot config magic: %d\n", ret);
-		goto out;
+		goto out_rollback;
 	}
 	ret = 0;
 out:
@@ -405,6 +416,14 @@ static int apply_xbc(const char *path, const char *xbc_path)
 	free(data);
 
 	return ret;
+
+out_rollback:
+	if (ftruncate(fd, stat.st_size) < 0) {
+		ret = -errno;
+		pr_err("Failed to rollback the write error: %d\n", ret);
+		pr_err("The initrd %s may be corrupted. Recommend to rebuild.\n", path);
+	}
+	goto out;
 }
 
 static int usage(void)