Fixes #46775 -- don't mutate the process's environment in Command::exec #55359
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
|
r? @aidanhs (rust_highfive has picked a reviewer for you, use r? to override) |
rust-highfive
added
the
S-waiting-on-review
|
The job Click to expand the log.I'm a bot! I can only do what humans tell me to, so if this was not helpful or you have suggestions for improvements, please ping or otherwise contact |
|
I don't see how I could have broken compiletests, with a libstd fix? |
|
The failure in question is https://github.com/rust-lang/rust/blob/master/src/test/run-pass-fulldeps/issue-15149.rs which used |
|
Ooof, this one is a mess. With the previous logic, the env was mutated so the current process's env contained a modified That's a frustrating mess, the only workaround that comes to mind is implementing |
|
TBH I wouldn't even expect the |
|
Unfortunately #15149 indicates that this was an intentional decision, so we can't just break it. |
|
Oh this is so sad :( So the original Unix implementation used a strange way to change the child's environment (not using |
alex
force-pushed
the
command-exec-uaf
branch
from
dee48bf
to
34ab6a3
Compare
|
The job Click to expand the log.I'm a bot! I can only do what humans tell me to, so if this was not helpful or you have suggestions for improvements, please ping or otherwise contact |
alex
force-pushed
the
command-exec-uaf
branch
from
34ab6a3
to
13c6fb7
Compare
|
The job Click to expand the log.I'm a bot! I can only do what humans tell me to, so if this was not helpful or you have suggestions for improvements, please ping or otherwise contact |
alex
force-pushed
the
command-exec-uaf
branch
from
13c6fb7
to
1c07f4d
Compare
alex
force-pushed
the
command-exec-uaf
branch
from
1c07f4d
to
fc770ea
Compare
|
@alexcrichton I think I got 'em both. |
|
@bors: r+ Thanks! |
|
📌 Commit fc770eaed19d1bc488cfa4632889edc107a7d813 has been approved by |
bors
added
S-waiting-on-bors
alexcrichton
added
beta-nominated
|
@bors: p=1 We'll want to be sure to backport this, so raising priority |
|
@bors: r+ p=1 er oops, didn't mean to close |
|
💡 This pull request was already approved, no need to approve it again.
|
alexcrichton
added
stable-accepted
pietroalbini
removed
the
beta-nominated
pietroalbini
added
stable-accepted
alexcrichton
added a commit
to alexcrichton/rust
that referenced
this pull request
Nov 13, 2018
This commit, after reverting rust-lang#55359, applies a different fix for rust-lang#46775 while also fixing rust-lang#55775. The basic idea was to go back to pre-rust-lang#55359 libstd, and then fix rust-lang#46775 in a way that doesn't expose rust-lang#55775. The issue described in rust-lang#46775 boils down to two problems: * First, the global environment is reset during `exec` but, but if the `exec` call fails then the global environment was a dangling pointer into free'd memory as the block of memory was deallocated when `Command` is dropped. This is fixed in this commit by installing a `Drop` stack object which ensures that the `environ` pointer is preserved on a failing `exec`. * Second, the global environment was accessed in an unsynchronized fashion during `exec`. This was fixed by ensuring that the Rust-specific environment lock is acquired for these system-level operations. Thanks to Alex Gaynor for pioneering the solution here! Closes rust-lang#55775 Co-authored-by: Alex Gaynor <alex.gaynor@gmail.com>
bors
added a commit
that referenced
this pull request
Nov 14, 2018
std: Synchronize access to global env during `exec` This commit, after reverting #55359, applies a different fix for #46775 while also fixing #55775. The basic idea was to go back to pre-#55359 libstd, and then fix #46775 in a way that doesn't expose #55775. The issue described in #46775 boils down to two problems: * First, the global environment is reset during `exec` but, but if the `exec` call fails then the global environment was a dangling pointer into free'd memory as the block of memory was deallocated when `Command` is dropped. This is fixed in this commit by installing a `Drop` stack object which ensures that the `environ` pointer is preserved on a failing `exec`. * Second, the global environment was accessed in an unsynchronized fashion during `exec`. This was fixed by ensuring that the Rust-specific environment lock is acquired for these system-level operations. Thanks to Alex Gaynor for pioneering the solution here! Closes #55775
alexcrichton
added a commit
to alexcrichton/rust
that referenced
this pull request
Nov 14, 2018
This commit, after reverting rust-lang#55359, applies a different fix for rust-lang#46775 while also fixing rust-lang#55775. The basic idea was to go back to pre-rust-lang#55359 libstd, and then fix rust-lang#46775 in a way that doesn't expose rust-lang#55775. The issue described in rust-lang#46775 boils down to two problems: * First, the global environment is reset during `exec` but, but if the `exec` call fails then the global environment was a dangling pointer into free'd memory as the block of memory was deallocated when `Command` is dropped. This is fixed in this commit by installing a `Drop` stack object which ensures that the `environ` pointer is preserved on a failing `exec`. * Second, the global environment was accessed in an unsynchronized fashion during `exec`. This was fixed by ensuring that the Rust-specific environment lock is acquired for these system-level operations. Thanks to Alex Gaynor for pioneering the solution here! Closes rust-lang#55775 Co-authored-by: Alex Gaynor <alex.gaynor@gmail.com>
bors
added a commit
that referenced
this pull request
Nov 14, 2018
std: Synchronize access to global env during `exec` This commit, after reverting #55359, applies a different fix for #46775 while also fixing #55775. The basic idea was to go back to pre-#55359 libstd, and then fix #46775 in a way that doesn't expose #55775. The issue described in #46775 boils down to two problems: * First, the global environment is reset during `exec` but, but if the `exec` call fails then the global environment was a dangling pointer into free'd memory as the block of memory was deallocated when `Command` is dropped. This is fixed in this commit by installing a `Drop` stack object which ensures that the `environ` pointer is preserved on a failing `exec`. * Second, the global environment was accessed in an unsynchronized fashion during `exec`. This was fixed by ensuring that the Rust-specific environment lock is acquired for these system-level operations. Thanks to Alex Gaynor for pioneering the solution here! Closes #55775
alexcrichton
added a commit
to alexcrichton/rust
that referenced
this pull request
Nov 15, 2018
This commit, after reverting rust-lang#55359, applies a different fix for rust-lang#46775 while also fixing rust-lang#55775. The basic idea was to go back to pre-rust-lang#55359 libstd, and then fix rust-lang#46775 in a way that doesn't expose rust-lang#55775. The issue described in rust-lang#46775 boils down to two problems: * First, the global environment is reset during `exec` but, but if the `exec` call fails then the global environment was a dangling pointer into free'd memory as the block of memory was deallocated when `Command` is dropped. This is fixed in this commit by installing a `Drop` stack object which ensures that the `environ` pointer is preserved on a failing `exec`. * Second, the global environment was accessed in an unsynchronized fashion during `exec`. This was fixed by ensuring that the Rust-specific environment lock is acquired for these system-level operations. Thanks to Alex Gaynor for pioneering the solution here! Closes rust-lang#55775 Co-authored-by: Alex Gaynor <alex.gaynor@gmail.com>
ischeinkman
pushed a commit
to ischeinkman/libnx-rs-std
that referenced
this pull request
Dec 20, 2018
This commit, after reverting rust-lang#55359, applies a different fix for rust-lang#46775 while also fixing rust-lang#55775. The basic idea was to go back to pre-rust-lang#55359 libstd, and then fix rust-lang#46775 in a way that doesn't expose rust-lang#55775. The issue described in rust-lang#46775 boils down to two problems: * First, the global environment is reset during `exec` but, but if the `exec` call fails then the global environment was a dangling pointer into free'd memory as the block of memory was deallocated when `Command` is dropped. This is fixed in this commit by installing a `Drop` stack object which ensures that the `environ` pointer is preserved on a failing `exec`. * Second, the global environment was accessed in an unsynchronized fashion during `exec`. This was fixed by ensuring that the Rust-specific environment lock is acquired for these system-level operations. Thanks to Alex Gaynor for pioneering the solution here! Closes rust-lang#55775 Co-authored-by: Alex Gaynor <alex.gaynor@gmail.com>
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Instead, pass the environment to execvpe, so the kernel can apply it directly to the new process. This avoids a use-after-free in the case where exec'ing the new process fails for any reason, as well as a race condition if there are other threads alive during the exec.
Fixes #46775