From: Indu Bhagat <ibhagat@sourceware.org>
To: bfd-cvs@sourceware.org, gdb-cvs@sourceware.org
Subject: [binutils-gdb] libsframe: adjust an incorrect check in flip_sframe
Date: Fri, 6 Jan 2023 17:45:29 +0000 (GMT) [thread overview]
Message-ID: <20230106174529.291503858D28@sourceware.org> (raw)
https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=cd9aea32cffd8089f6f63f4eb86d4dccfc0b3850
commit cd9aea32cffd8089f6f63f4eb86d4dccfc0b3850
Author: Indu Bhagat <indu.bhagat@oracle.com>
Date: Fri Jan 6 09:29:48 2023 -0800
libsframe: adjust an incorrect check in flip_sframe
When sframe_encoder_write needs to flip the buffer containing the SFrame
section before writing, it is not necessary that the SFrame FDES are in
the order of their sfde_func_start_fre_off. On the contrary, SFrame
FDEs will be sorted in the order of their start address. So, remove
this incorrect assumption which is basically assuming that the last
sfde_func_start_fre_off seen will help determine the end of the flipped
buffer.
The function now keeps track of the bytes_flipped and then compares it with
the expected value. Also, added two more checks at appropriate places:
- check that the SFrame FDE read is within bounds
- check that the SFrame FRE read is within bounds
libsframe/
* sframe.c (flip_sframe): Adjust an incorrect check.
Add other checks to ensure reads are within the buffer size.
Diff:
---
libsframe/sframe.c | 22 +++++++++++++---------
1 file changed, 13 insertions(+), 9 deletions(-)
diff --git a/libsframe/sframe.c b/libsframe/sframe.c
index 4aada1a25e0..d206780289a 100644
--- a/libsframe/sframe.c
+++ b/libsframe/sframe.c
@@ -401,7 +401,10 @@ flip_sframe (char *frame_buf, size_t buf_size, uint32_t to_foreign)
unsigned int fre_type = 0;
uint32_t fre_offset = 0;
size_t esz = 0;
+ size_t hdrsz = 0;
int err = 0;
+ /* For error checking. */
+ size_t bytes_flipped = 0;
/* Header must be in host endianness at this time. */
ihp = (sframe_header *)frame_buf;
@@ -411,14 +414,18 @@ flip_sframe (char *frame_buf, size_t buf_size, uint32_t to_foreign)
/* The contents of the SFrame header are safe to read. Get the number of
FDEs and the first FDE in the buffer. */
+ hdrsz = sframe_get_hdr_size (ihp);
num_fdes = ihp->sfh_num_fdes;
- fdes = frame_buf + sframe_get_hdr_size (ihp) + ihp->sfh_fdeoff;
+ fdes = frame_buf + hdrsz + ihp->sfh_fdeoff;
fdep = (sframe_func_desc_entry *)fdes;
j = 0;
prev_frep_index = 0;
for (i = 0; i < num_fdes; fdep++, i++)
{
+ if ((char*)fdep >= (frame_buf + buf_size))
+ goto bad;
+
if (to_foreign)
{
num_fres = fdep->sfde_func_num_fres;
@@ -427,6 +434,7 @@ flip_sframe (char *frame_buf, size_t buf_size, uint32_t to_foreign)
}
flip_fde (fdep);
+ bytes_flipped += sizeof (sframe_func_desc_entry);
if (!to_foreign)
{
@@ -441,20 +449,16 @@ flip_sframe (char *frame_buf, size_t buf_size, uint32_t to_foreign)
{
if (flip_fre (fp, fre_type, &esz))
goto bad;
+ bytes_flipped += esz;
- if (esz == 0)
+ if (esz == 0 || esz > buf_size)
goto bad;
fp += esz;
}
prev_frep_index = j;
}
- /* All FREs must have been endian flipped by now. */
- if (j != ihp->sfh_num_fres)
- goto bad;
- /* Contents, if any, must have been processed by now.
- Recall that .sframe section with just a SFrame header may be generated by
- GAS if no SFrame FDEs were found for the input file. */
- if (ihp->sfh_num_fres && ((frame_buf + buf_size) != (void*)fp))
+ /* All FDEs and FREs must have been endian flipped by now. */
+ if ((j != ihp->sfh_num_fres) || (bytes_flipped != (buf_size - hdrsz)))
goto bad;
/* Success. */
reply other threads:[~2023-01-06 17:45 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20230106174529.291503858D28@sourceware.org \
--to=ibhagat@sourceware.org \
--cc=bfd-cvs@sourceware.org \
--cc=gdb-cvs@sourceware.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).