From: Indu Bhagat <indu.bhagat@oracle.com>
To: binutils@sourceware.org
Cc: Indu Bhagat <indu.bhagat@oracle.com>
Subject: [PATCH] libsframe: adjust an incorrect check in flip_sframe
Date: Tue, 3 Jan 2023 22:56:11 -0800 [thread overview]
Message-ID: <20230104065611.377771-1-indu.bhagat@oracle.com> (raw)
Hello,
While testing the endian flipping code in libsframe, I tried a cross build with
--target=x86_64-linux on a big-endian system (ppc64), and I ran into some
SFrame testsuite failures:
FAIL: SFrame Simple link
FAIL: SFrame for plt0 and pltN
The reason for failure is explained below in the commit log. This patch fixes
the issue.
Testing notes:
- Reg tested native and cross builds on x86_64 and aarch64 (checked binutils,
ld, gas, libctf, libsframe).
- try bot shows no new regressions.
- Tested ld, gas with a cross build: --target=x86_64-linux on ppc64 host. The
two testcase failures are resolved with this patch.
Before the patch:
FAIL: SFrame Simple link
FAIL: SFrame for plt0 and pltN
=== ld Summary ===
# of expected passes 1651
# of unexpected failures 2
# of expected failures 3
# of untested testcases 26
# of unsupported tests 134
After the patch:
=== ld Summary ===
# of expected passes 1653
# of expected failures 3
# of untested testcases 26
# of unsupported tests 134
OK for master and binutils-2_40-branch ?
Thanks
--------------------------------------
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
ChangeLog:
* libsframe/sframe.c (flip_sframe): Adjust an incorrect check.
Add other checks to ensure reads are within the buffer size.
---
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. */
--
2.37.2
next reply other threads:[~2023-01-04 6:56 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-04 6:56 Indu Bhagat [this message]
2023-01-06 17:56 ` Indu Bhagat
2023-01-09 10:16 ` Nick Clifton
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