[BUG FIX] false alarm for non overlapping sections #230

rmNULL · 2020-08-18T17:11:49Z

What these changes do

avoids recheck of marked note segments already synced with note sections,

This also serves as a bug fix when a previously synced note segment
overlaps with another section.

Steps to reproduce the bug

pushd /tmp

wget -O util-linux.bottle.tar.gz "https://bintray.com/linuxbrew/bottles/download_file?file_path=util-linux-2.36.x86_64_linux.bottle.tar.gz"
tar -zxf util-linux.bottle.tar.gz
chmod +w util-linux/2.36/bin/chmem
patchelf --force-rpath --set-rpath "ngcfpqardtudtlvqujdskyvgehsyxyxawbqchomweuxfbvfrfekhgnrtlsftwwjcpvoyedaoaikgkgyxmodpkafkcubibuiasuabbziihwijnfjnsqpqmlcwzxzxvphnclpqezyjrtetcmomldsh" /tmp/util-linux/2.36/bin/chmem

Description of bug

Running the above described commands fails with

patchelf: unsupported overlap of SHT_NOTE and PT_NOTE

why is this happening ?

patchelf/src/patchelf.cc

Lines 725 to 741 in 7aa6b90

    
           Elf_Off p_start = rdi(phdrs[j].p_offset); 
        
           Elf_Off p_end = p_start + rdi(phdrs[j].p_filesz); 
        
           Elf_Off s_start = rdi(orig_shdr.sh_offset); 
        
           Elf_Off s_end = s_start + rdi(orig_shdr.sh_size); 
        
           /* Skip if no overlap. */ 
        
           if (!(s_start >= p_start && s_start < p_end) && 
        
               !(s_end > p_start && s_end <= p_end)) 
        
               continue; 
        
           /* We only support exact matches. */ 
        
           if (p_start != s_start || p_end != s_end) 
        
               error("unsupported overlap of SHT_NOTE and PT_NOTE"); 
        
           phdrs[j].p_offset = shdr.sh_offset; 
        
           phdrs[j].p_vaddr = phdrs[j].p_paddr = shdr.sh_addr; 
        
           phdrs[j].p_filesz = phdrs[j].p_memsz = shdr.sh_size;

In the above link, the previously updated program header will be compared against un updated section header(orig_shdr)

verbose explanation

i'll paste the PATCHELF_DEBUG=1 log here,
if the log makes sense, please skip the writing.

patching ELF file '/tmp/util-linux/2.36/bin/chmem'
new rpath is 'ngcfpqardtudtlvqujdskyvgehsyxyxawbqchomweuxfbvfrfekhgnrtlsftwwjcpvoyedaoaikgkgyxmodpkafkcubibuiasuabbziihwijnfjnsqpqmlcwzxzxvphnclpqezyjrtetcmomldsh'
rpath is too long, resizing...
replacing section '.dynstr' with size 1365
this is an executable
using replaced section '.dynstr'
last replaced is 6
looking at section '.interp'
replacing section '.interp' which is in the way
looking at section '.note.ABI-tag'
replacing section '.note.ABI-tag' which is in the way
looking at section '.note.gnu.build-id'
replacing section '.note.gnu.build-id' which is in the way
looking at section '.gnu.hash'
replacing section '.gnu.hash' which is in the way
looking at section '.dynsym'
replacing section '.dynsym' which is in the way
looking at section '.dynstr'
first reserved offset/addr is 0x11b0/0x4011b0
first page is 0x400000
needed space is 4728
needed space is 4784
needed pages is 1
changing alignment of program header 2 from 2097152 to 4096
changing alignment of program header 6 from 2097152 to 4096
clearing first 7944 bytes
rewriting section '.dynstr' from offset 0x1cf0 (size 1216) to offset 0x2a8 (size 1365)
rewriting section '.dynsym' from offset 0x12e8 (size 2568) to offset 0x800 (size 2568)
rewriting section '.gnu.hash' from offset 0x12a8 (size 64) to offset 0x1208 (size 64)
rewriting section '.interp' from offset 0x1238 (size 30) to offset 0x1248 (size 30)
rewriting section '.note.ABI-tag' from offset 0x1260 (size 32) to offset 0x1268 (size 32)
rewriting section '.note.gnu.build-id' from offset 0x1280 (size 36) to offset 0x1288 (size 36)
patchelf: unsupported overlap of SHT_NOTE and PT_NOTE

orig_shdr = .note.ABI-tag is at 0x1260
it finds a matching segment from 0x1260 to 0x1280
and updates the phdr values to new shdr values
which is 0x1268 .. 0x1288

for the next replaced_section
orig_shdr = .note.gnu.build-id is at 0x1280
it checks for overlap between 0x1280 .. 0x12a4
the previously updated phdr( 0x1268 .. 0x1288)
overlaps with this section.

phew 😥

Another point being,
it doesn't make sense to check the program once mapped to section
as the whole point of normalize note sections is to create 1 - 1 mapping
between section and segments.

Alternative ways to resolve the issue are welcome.
Thanks

sjackman

Suggested aesthetic improvements. Looks good!

src/patchelf.cc

domenkozar · 2020-08-19T15:39:16Z

Would be great to add a regression test.

rmNULL · 2020-08-21T14:38:51Z

@domenkozar
sorry im new here, i see the commit(https://github.com/NixOS/patchelf/blob/master/tests/build-id.sh) as "regression test",
will a test in similar nature do ?

domenkozar · 2020-08-24T08:48:30Z

@rmNULL exactly!

…e sections to segments. This also serves as a bug fix when a previously synced note segment overlaps with another section and creates a false alarm.

aaronjanse · 2020-10-16T22:57:43Z

I think I just ran into this while packaging Energia (https://energia.nu)

https://gist.github.com/aaronjanse/fa6d76c57c5e07c49dfe6094e4dd7de8

sjackman · 2020-11-18T21:36:15Z

@delroth @Mic92 @edolstra Are you able to give this PR a review? It's a blocker for Homebrew on Linux.

See NixOS/patchelf#230

See NixOS/patchelf#230 Closes #65137. Signed-off-by: Michka Popoff <3406519+iMichka@users.noreply.github.com>

Mic92 · 2020-11-19T06:37:36Z

@sjackman I cannot merge PRs here, but I know from experience that bug fixes with tests get merged faster, i.e. #251

sjackman · 2020-11-19T18:12:55Z

Thank you for merging, Eelco! 🌟

sjackman · 2020-11-19T18:13:14Z

and thank you for the fix, @rmNULL! 🏆

Starting with version 0.12, patchelf sometimes returns an error complaining about overlapping sections: > unsupported overlap of SHT_NOTE and PT_NOTE This issue was reported for tsm-client: NixOS#106257 There is a patch available in this pull request: NixOS/patchelf#230 This patch fixes tsm-client, maybe other packages as well. This commit adds the patch to the nixpkgs patchelf build recipe. Note that the patch may also be downloaded directly here: https://github.com/NixOS/patchelf/pull/230.patch However, in contrast to common nixpkgs policy, the patch is not fetched with fetchpatch, but is copied directly into nixpkgs tree. This is necessary because patchelf is a dependency of fetchpatch. See also the note at the top of the patchelf build recipe in pkgs/development/tools/misc/patchelf/default.nix .

sjackman suggested changes Aug 18, 2020

View reviewed changes

src/patchelf.cc Show resolved Hide resolved

src/patchelf.cc Show resolved Hide resolved

src/patchelf.cc Show resolved Hide resolved

mark phdrs synced with sections, avoid rechecking it when syncing not…

6edec83

…e sections to segments. This also serves as a bug fix when a previously synced note segment overlaps with another section and creates a false alarm.

rmNULL force-pushed the fix-wrong-unsupported-overlap branch 2 times, most recently from 15c9d7e to 6edec83 Compare August 25, 2020 22:29

0x4A6F mentioned this pull request Sep 10, 2020

egalaxtouch: init at 2.5.9321 NixOS/nixpkgs#65394

Closed

10 tasks

sjackman added a commit to sjackman/homebrew-core that referenced this pull request Nov 18, 2020

patchelf: Fix unsupported overlap of SHT_NOTE and PT_NOTE

f76184c

See NixOS/patchelf#230

sjackman mentioned this pull request Nov 18, 2020

patchelf: Fix unsupported overlap of SHT_NOTE and PT_NOTE Homebrew/homebrew-core#65137

Closed

5 tasks

BrewTestBot pushed a commit to Homebrew/homebrew-core that referenced this pull request Nov 18, 2020

patchelf: Fix unsupported overlap of SHT_NOTE and PT_NOTE

df1e849

See NixOS/patchelf#230 Closes #65137. Signed-off-by: Michka Popoff <3406519+iMichka@users.noreply.github.com>

edolstra merged commit 81a48fd into NixOS:master Nov 19, 2020

This was referenced Dec 8, 2020

patchelf: add patch: false alarm for non overlapping sections NixOS/nixpkgs#106340

Closed

tsm-client package: broken on 20.09 due to "patchelf: unsupported overlap of SHT_NOTE and PT_NOTE" NixOS/nixpkgs#106257

Closed

domenkozar mentioned this pull request Dec 8, 2020

unsupported overlap of SHT_NOTE and PT_NOTE with Rust ELF files #255

Closed

This was referenced Apr 17, 2021

Add pr #230 to patchelf as it is currently broken spack/spack#23063

Merged

New release? #272

Closed

antirotor mentioned this pull request Jun 29, 2021

switch PyQt5 for PySide2 ynput/OpenPype#1744

Merged

17 tasks

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

[BUG FIX] false alarm for non overlapping sections #230

[BUG FIX] false alarm for non overlapping sections #230

rmNULL commented Aug 18, 2020

sjackman left a comment

domenkozar commented Aug 19, 2020

rmNULL commented Aug 21, 2020

domenkozar commented Aug 24, 2020

aaronjanse commented Oct 16, 2020

sjackman commented Nov 18, 2020

Mic92 commented Nov 19, 2020

sjackman commented Nov 19, 2020

sjackman commented Nov 19, 2020

	Elf_Off p_start = rdi(phdrs[j].p_offset);
	Elf_Off p_end = p_start + rdi(phdrs[j].p_filesz);
	Elf_Off s_start = rdi(orig_shdr.sh_offset);
	Elf_Off s_end = s_start + rdi(orig_shdr.sh_size);

	/* Skip if no overlap. */
	if (!(s_start >= p_start && s_start < p_end) &&
	!(s_end > p_start && s_end <= p_end))
	continue;

	/* We only support exact matches. */
	if (p_start != s_start \|\| p_end != s_end)
	error("unsupported overlap of SHT_NOTE and PT_NOTE");

	phdrs[j].p_offset = shdr.sh_offset;
	phdrs[j].p_vaddr = phdrs[j].p_paddr = shdr.sh_addr;
	phdrs[j].p_filesz = phdrs[j].p_memsz = shdr.sh_size;

[BUG FIX] false alarm for non overlapping sections #230

[BUG FIX] false alarm for non overlapping sections #230

Conversation

rmNULL commented Aug 18, 2020

What these changes do

Steps to reproduce the bug

Description of bug

why is this happening ?

verbose explanation

sjackman left a comment

Choose a reason for hiding this comment

domenkozar commented Aug 19, 2020

rmNULL commented Aug 21, 2020

domenkozar commented Aug 24, 2020

aaronjanse commented Oct 16, 2020

sjackman commented Nov 18, 2020

Mic92 commented Nov 19, 2020

sjackman commented Nov 19, 2020

sjackman commented Nov 19, 2020