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Message-ID: <442be8d5f2810aa8e04c3529c822438f948075b3.1657272362.git.noodles@fb.com>
Date: Fri, 8 Jul 2022 10:11:48 +0000
From: Jonathan McDowell <noodles@...com>
To: "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"linux-fsdevel@...r.kernel.org" <linux-fsdevel@...r.kernel.org>,
"linux-integrity@...r.kernel.org" <linux-integrity@...r.kernel.org>,
"linux-security-module@...r.kernel.org"
<linux-security-module@...r.kernel.org>,
"kexec@...ts.infradead.org" <kexec@...ts.infradead.org>
CC: Alexander Viro <viro@...iv.linux.org.uk>,
Mimi Zohar <zohar@...ux.ibm.com>,
Dmitry Kasatkin <dmitry.kasatkin@...il.com>,
James Morris <jmorris@...ei.org>,
"Serge E. Hallyn" <serge@...lyn.com>,
Matthew Garrett <mjg59@...f.ucam.org>,
Dmitrii Potoskuev <dpotoskuev@...com>
Subject: [RFC PATCH 2/7] lib/cpio: Improve error handling
As preparation for making the cpio parsing routines more generally
available improve the error handling such that we pass back a suitable
errno rather than a string message, and correctly exit execution when
such an error is raised.
Signed-off-by: Jonathan McDowell <noodles@...com>
---
include/linux/cpio.h | 1 -
init/initramfs.c | 10 ++++++--
lib/cpio.c | 56 +++++++++++++++++++++++++++-----------------
3 files changed, 43 insertions(+), 24 deletions(-)
diff --git a/include/linux/cpio.h b/include/linux/cpio.h
index f90b53fda6b5..d8c1344a6cc3 100644
--- a/include/linux/cpio.h
+++ b/include/linux/cpio.h
@@ -43,7 +43,6 @@ struct cpio_context {
unsigned long byte_count;
bool csum_present;
u32 io_csum;
- char *errmsg;
char *collected;
long remains;
diff --git a/init/initramfs.c b/init/initramfs.c
index 5e3abc1e51cc..3670fe0ac336 100644
--- a/init/initramfs.c
+++ b/init/initramfs.c
@@ -62,10 +62,16 @@ static char * __init unpack_to_rootfs(char *buf, unsigned long len)
if (*buf == '0' && !(ctx.this_header & 3)) {
ctx.state = CPIO_START;
written = cpio_write_buffer(&ctx, buf, len);
+
+ if (written < 0) {
+ pr_err("Failed to process archive: %ld\n",
+ written);
+ error("failed to process archive");
+ break;
+ }
+
buf += written;
len -= written;
- if (ctx.errmsg)
- message = ctx.errmsg;
continue;
}
if (!*buf) {
diff --git a/lib/cpio.c b/lib/cpio.c
index c71bebd4cc98..5d150939704f 100644
--- a/lib/cpio.c
+++ b/lib/cpio.c
@@ -221,12 +221,10 @@ static int __init do_header(struct cpio_context *ctx)
ctx->csum_present = false;
} else if (!memcmp(ctx->collected, "070702", 6)) {
ctx->csum_present = true;
+ } else if (memcmp(ctx->collected, "070707", 6) == 0) {
+ return -EPROTONOSUPPORT;
} else {
- if (memcmp(ctx->collected, "070707", 6) == 0)
- ctx->errmsg = "incorrect cpio method used: use -H newc option";
- else
- ctx->errmsg = "no cpio magic";
- return 1;
+ return -EINVAL;
}
parse_header(ctx, ctx->collected);
ctx->next_header = ctx->this_header + N_ALIGN(ctx->name_len) + ctx->body_len;
@@ -266,7 +264,8 @@ static int __init do_reset(struct cpio_context *ctx)
while (ctx->byte_count && *ctx->victim == '\0')
eat(ctx, 1);
if (ctx->byte_count && (ctx->this_header & 3))
- ctx->errmsg = "broken padding";
+ return -EFAULT;
+
return 1;
}
@@ -344,23 +343,29 @@ static int __init do_name(struct cpio_context *ctx)
static int __init do_copy(struct cpio_context *ctx)
{
+ int ret;
+
if (ctx->byte_count >= ctx->body_len) {
- if (xwrite(ctx, ctx->wfile, ctx->victim, ctx->body_len,
- &ctx->wfile_pos) != ctx->body_len)
- ctx->errmsg = "write error";
+ ret = xwrite(ctx, ctx->wfile, ctx->victim, ctx->body_len,
+ &ctx->wfile_pos);
+ if (ret != ctx->body_len)
+ return (ret < 0) ? ret : -EIO;
do_utime_path(&ctx->wfile->f_path, ctx->mtime);
fput(ctx->wfile);
if (ctx->csum_present && ctx->io_csum != ctx->hdr_csum)
- ctx->errmsg = "bad data checksum";
+ return -EBADMSG;
+
eat(ctx, ctx->body_len);
ctx->state = CPIO_SKIPIT;
return 0;
}
- if (xwrite(ctx, ctx->wfile, ctx->victim, ctx->byte_count,
- &ctx->wfile_pos) != ctx->byte_count)
- ctx->errmsg = "write error";
+ ret = xwrite(ctx, ctx->wfile, ctx->victim, ctx->byte_count,
+ &ctx->wfile_pos);
+ if (ret != ctx->byte_count)
+ return (ret < 0) ? ret : -EIO;
+
ctx->body_len -= ctx->byte_count;
eat(ctx, ctx->byte_count);
return 1;
@@ -392,12 +397,19 @@ static __initdata int (*actions[])(struct cpio_context *) = {
long __init cpio_write_buffer(struct cpio_context *ctx, char *buf,
unsigned long len)
{
+ int ret;
+
ctx->byte_count = len;
ctx->victim = buf;
- while (!actions[ctx->state](ctx))
- ;
- return len - ctx->byte_count;
+ ret = 0;
+ while (ret == 0)
+ ret = actions[ctx->state](ctx);
+
+ if (ret < 0)
+ return ret;
+ else
+ return len - ctx->byte_count;
}
long __init cpio_process_buffer(struct cpio_context *ctx, void *bufv,
@@ -407,11 +419,13 @@ long __init cpio_process_buffer(struct cpio_context *ctx, void *bufv,
long written;
long left = len;
- if (ctx->errmsg)
- return -1;
+ while ((written = cpio_write_buffer(ctx, buf, left)) < left) {
+ char c;
+
+ if (written < 0)
+ return written;
- while ((written = cpio_write_buffer(ctx, buf, left)) < left && !ctx->errmsg) {
- char c = buf[written];
+ c = buf[written];
if (c == '0') {
buf += written;
@@ -422,7 +436,7 @@ long __init cpio_process_buffer(struct cpio_context *ctx, void *bufv,
left -= written;
ctx->state = CPIO_RESET;
} else {
- ctx->errmsg = "junk within compressed archive";
+ return -EINVAL;
}
}
--
2.36.1
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