Merge branch 'js/fix-open-exec'

This addresses CVE-2025-46835, Git GUI can create and overwrite a
user's files:

When a user clones an untrusted repository and is tricked into editing
a file located in a maliciously named directory in the repository, then
Git GUI can create and overwrite files for which the user has write
permission.

Signed-off-by: Johannes Sixt <j6t@kdbg.org>

Author: j6t

git-gui/git-gui.sh

@@ -481,14 +481,14 @@ method _load {jump} {
 		if {$do_textconv ne 0} {
 			set fd [open_cmd_pipe $textconv $path]
 		} else {
-			set fd [open $path r]
+			set fd [safe_open_file $path r]
 		}
 		fconfigure $fd -eofchar {}
 	} else {
 		if {$do_textconv ne 0} {
-			set fd [git_read cat-file --textconv "$commit:$path"]
+			set fd [git_read [list cat-file --textconv "$commit:$path"]]
 		} else {
-			set fd [git_read cat-file blob "$commit:$path"]
+			set fd [git_read [list cat-file blob "$commit:$path"]]
 		}
 	}
 	fconfigure $fd \
@@ -617,7 +617,7 @@ method _exec_blame {cur_w cur_d options cur_s} {
 	}
 
 	lappend options -- $path
-	set fd [eval git_read --nice blame $options]
+	set fd [git_read_nice [concat blame $options]]
 	fconfigure $fd -blocking 0 -translation lf -encoding utf-8
 	fileevent $fd readable [cb _read_blame $fd $cur_w $cur_d]
 	set current_fd $fd
@@ -986,7 +986,7 @@ method _showcommit {cur_w lno} {
 		if {[catch {set msg $header($cmit,message)}]} {
 			set msg {}
 			catch {
-				set fd [git_read cat-file commit $cmit]
+				set fd [git_read [list cat-file commit $cmit]]
 				fconfigure $fd -encoding binary -translation lf
 				# By default commits are assumed to be in utf-8
 				set enc utf-8
@@ -1134,7 +1134,7 @@ method _blameparent {} {
 		} else {
 			set diffcmd [list diff-tree --unified=0 $cparent $cmit -- $new_path]
 		}
-		if {[catch {set fd [eval git_read $diffcmd]} err]} {
+		if {[catch {set fd [git_read $diffcmd]} err]} {
 			$status_operation stop [mc "Unable to display parent"]
 			error_popup [strcat [mc "Error loading diff:"] "\n\n$err"]
 			return

git-gui/lib/blame.tcl

@@ -7,7 +7,7 @@ proc load_all_heads {} {
 	set rh refs/heads
 	set rh_len [expr {[string length $rh] + 1}]
 	set all_heads [list]
-	set fd [git_read for-each-ref --format=%(refname) $rh]
+	set fd [git_read [list for-each-ref --format=%(refname) $rh]]
 	fconfigure $fd -translation binary -encoding utf-8
 	while {[gets $fd line] > 0} {
 		if {!$some_heads_tracking || ![is_tracking_branch $line]} {
@@ -21,10 +21,10 @@ proc load_all_heads {} {
 
 proc load_all_tags {} {
 	set all_tags [list]
-	set fd [git_read for-each-ref \
+	set fd [git_read [list for-each-ref \
 		--sort=-taggerdate \
 		--format=%(refname) \
-		refs/tags]
+		refs/tags]]
 	fconfigure $fd -translation binary -encoding utf-8
 	while {[gets $fd line] > 0} {
 		if {![regsub ^refs/tags/ $line {} name]} continue

git-gui/lib/branch.tcl

@@ -196,7 +196,7 @@ method _ls {tree_id {name {}}} {
 	lappend browser_stack [list $tree_id $name]
 	$w conf -state disabled
 
-	set fd [git_read ls-tree -z $tree_id]
+	set fd [git_read [list ls-tree -z $tree_id]]
 	fconfigure $fd -blocking 0 -translation binary -encoding utf-8
 	fileevent $fd readable [cb _read $fd]
 }

git-gui/lib/browser.tcl

@@ -304,12 +304,12 @@ The rescan will be automatically started now.
 		_readtree $this
 	} else {
 		ui_status [mc "Refreshing file status..."]
-		set fd [git_read update-index \
+		set fd [git_read [list update-index \
 			-q \
 			--unmerged \
 			--ignore-missing \
 			--refresh \
-			]
+			]]
 		fconfigure $fd -blocking 0 -translation binary
 		fileevent $fd readable [cb _refresh_wait $fd]
 	}
@@ -345,14 +345,15 @@ method _readtree {} {
 		[mc "Updating working directory to '%s'..." [_name $this]] \
 		[mc "files checked out"]]
 
-	set fd [git_read --stderr read-tree \
+	set fd [git_read [list read-tree \
 		-m \
 		-u \
 		-v \
 		--exclude-per-directory=.gitignore \
 		$HEAD \
 		$new_hash \
-		]
+		] \
+		[list 2>@1]]
 	fconfigure $fd -blocking 0 -translation binary
 	fileevent $fd readable [cb _readtree_wait $fd $status_bar_operation]
 }
@@ -510,18 +511,8 @@ method _update_repo_state {} {
 	delete_this
 }
 
-git-version proc _detach_HEAD {log new} {
-	>= 1.5.3 {
-		git update-ref --no-deref -m $log HEAD $new
-	}
-	default {
-		set p [gitdir HEAD]
-		file delete $p
-		set fd [open $p w]
-		fconfigure $fd -translation lf -encoding utf-8
-		puts $fd $new
-		close $fd
-	}
+proc _detach_HEAD {log new} {
+	git update-ref --no-deref -m $log HEAD $new
 }
 
 method _confirm_reset {cur} {
@@ -582,7 +573,7 @@ method _confirm_reset {cur} {
 	pack $w.buttons.cancel -side right -padx 5
 	pack $w.buttons -side bottom -fill x -pady 10 -padx 10
 
-	set fd [git_read rev-list --pretty=oneline $cur ^$new_hash]
+	set fd [git_read [list rev-list --pretty=oneline $cur ^$new_hash]]
 	while {[gets $fd line] > 0} {
 		set abbr [string range $line 0 7]
 		set subj [string range $line 41 end]

git-gui/lib/checkout_op.tcl

@@ -641,8 +641,8 @@ method _do_clone2 {} {
 			set pwd [pwd]
 			if {[catch {
 				file mkdir [gitdir objects info]
-				set f_in [open [file join $objdir info alternates] r]
-				set f_cp [open [gitdir objects info alternates] w]
+				set f_in [safe_open_file [file join $objdir info alternates] r]
+				set f_cp [safe_open_file [gitdir objects info alternates] w]
 				fconfigure $f_in -translation binary -encoding binary
 				fconfigure $f_cp -translation binary -encoding binary
 				cd $objdir
@@ -727,7 +727,7 @@ method _do_clone2 {} {
 			[cb _do_clone_tags]
 	}
 	shared {
-		set fd [open [gitdir objects info alternates] w]
+		set fd [safe_open_file [gitdir objects info alternates] w]
 		fconfigure $fd -translation binary
 		puts $fd $objdir
 		close $fd
@@ -760,8 +760,8 @@ method _copy_files {objdir tocopy} {
 	}
 	foreach p $tocopy {
 		if {[catch {
-				set f_in [open [file join $objdir $p] r]
-				set f_cp [open [file join .git objects $p] w]
+				set f_in [safe_open_file [file join $objdir $p] r]
+				set f_cp [safe_open_file [file join .git objects $p] w]
 				fconfigure $f_in -translation binary -encoding binary
 				fconfigure $f_cp -translation binary -encoding binary
 
@@ -818,12 +818,12 @@ method _clone_refs {} {
 		error_popup [mc "Not a Git repository: %s" [file tail $origin_url]]
 		return 0
 	}
-	set fd_in [git_read for-each-ref \
+	set fd_in [git_read [list for-each-ref \
 		--tcl \
-		{--format=list %(refname) %(objectname) %(*objectname)}]
+		{--format=list %(refname) %(objectname) %(*objectname)}]]
 	cd $pwd
 
-	set fd [open [gitdir packed-refs] w]
+	set fd [safe_open_file [gitdir packed-refs] w]
 	fconfigure $fd -translation binary
 	puts $fd "# pack-refs with: peeled"
 	while {[gets $fd_in line] >= 0} {
@@ -877,7 +877,7 @@ method _do_clone_full_end {ok} {
 
 		set HEAD {}
 		if {[file exists [gitdir FETCH_HEAD]]} {
-			set fd [open [gitdir FETCH_HEAD] r]
+			set fd [safe_open_file [gitdir FETCH_HEAD] r]
 			while {[gets $fd line] >= 0} {
 				if {[regexp "^(.{40})\t\t" $line line HEAD]} {
 					break
@@ -953,13 +953,14 @@ method _do_clone_checkout {HEAD} {
 		[mc "files"]]
 
 	set readtree_err {}
-	set fd [git_read --stderr read-tree \
+	set fd [git_read [list read-tree \
 		-m \
 		-u \
 		-v \
 		HEAD \
 		HEAD \
-		]
+		] \
+		[list 2>@1]]
 	fconfigure $fd -blocking 0 -translation binary
 	fileevent $fd readable [cb _readtree_wait $fd]
 }

git-gui/lib/choose_repository.tcl

@@ -146,14 +146,14 @@ constructor _new {path unmerged_only title} {
 	append fmt { %(*subject)}
 	append fmt {]}
 	set all_refn [list]
-	set fr_fd [git_read for-each-ref \
+	set fr_fd [git_read [list for-each-ref \
 		--tcl \
 		--sort=-taggerdate \
 		--format=$fmt \
 		refs/heads \
 		refs/remotes \
 		refs/tags \
-		]
+		]]
 	fconfigure $fr_fd -translation lf -encoding utf-8
 	while {[gets $fr_fd line] > 0} {
 		set line [eval $line]
@@ -176,7 +176,7 @@ constructor _new {path unmerged_only title} {
 	close $fr_fd
 
 	if {$unmerged_only} {
-		set fr_fd [git_read rev-list --all ^$::HEAD]
+		set fr_fd [git_read [list rev-list --all ^$::HEAD]]
 		while {[gets $fr_fd sha1] > 0} {
 			if {[catch {set rlst $cmt_refn($sha1)}]} continue
 			foreach refn $rlst {
@@ -579,7 +579,7 @@ method _reflog_last {name} {
 
 	set last {}
 	if {[catch {set last [file mtime [gitdir $name]]}]
-	&& ![catch {set g [open [gitdir logs $name] r]}]} {
+	&& ![catch {set g [safe_open_file [gitdir logs $name] r]}]} {
 		fconfigure $g -translation binary
 		while {[gets $g line] >= 0} {
 			if {[regexp {> ([1-9][0-9]*) } $line line when]} {

git-gui/lib/choose_rev.tcl

@@ -27,7 +27,7 @@ You are currently in the middle of a merge that has not been fully completed.  Y
 	if {[catch {
 			set name ""
 			set email ""
-			set fd [git_read cat-file commit $curHEAD]
+			set fd [git_read [list cat-file commit $curHEAD]]
 			fconfigure $fd -encoding binary -translation lf
 			# By default commits are assumed to be in utf-8
 			set enc utf-8
@@ -225,7 +225,7 @@ A good commit message has the following format:
 	# -- Build the message file.
 	#
 	set msg_p [gitdir GITGUI_EDITMSG]
-	set msg_wt [open $msg_p w]
+	set msg_wt [safe_open_file $msg_p w]
 	fconfigure $msg_wt -translation lf
 	setup_commit_encoding $msg_wt
 	puts $msg_wt $msg
@@ -325,7 +325,7 @@ proc commit_commitmsg_wait {fd_ph curHEAD msg_p} {
 
 proc commit_writetree {curHEAD msg_p} {
 	ui_status [mc "Committing changes..."]
-	set fd_wt [git_read write-tree]
+	set fd_wt [git_read [list write-tree]]
 	fileevent $fd_wt readable \
 		[list commit_committree $fd_wt $curHEAD $msg_p]
 }
@@ -350,7 +350,7 @@ proc commit_committree {fd_wt curHEAD msg_p} {
 	# -- Verify this wasn't an empty change.
 	#
 	if {$commit_type eq {normal}} {
-		set fd_ot [git_read cat-file commit $PARENT]
+		set fd_ot [git_read [list cat-file commit $PARENT]]
 		fconfigure $fd_ot -encoding binary -translation lf
 		set old_tree [gets $fd_ot]
 		close $fd_ot
@@ -388,8 +388,8 @@ A rescan will be automatically started now.
 	foreach p [concat $PARENT $MERGE_HEAD] {
 		lappend cmd -p $p
 	}
-	lappend cmd <$msg_p
-	if {[catch {set cmt_id [eval git $cmd]} err]} {
+	set msgtxt [list <$msg_p]
+	if {[catch {set cmt_id [git_redir $cmd $msgtxt]} err]} {
 		catch {file delete $msg_p}
 		error_popup [strcat [mc "commit-tree failed:"] "\n\n$err"]
 		ui_status [mc "Commit failed."]
@@ -409,7 +409,7 @@ A rescan will be automatically started now.
 	if {$commit_type ne {normal}} {
 		append reflogm " ($commit_type)"
 	}
-	set msg_fd [open $msg_p r]
+	set msg_fd [safe_open_file $msg_p r]
 	setup_commit_encoding $msg_fd 1
 	gets $msg_fd subject
 	close $msg_fd

git-gui/lib/commit.tcl

@@ -92,10 +92,9 @@ method _init {} {
 
 method exec {cmd {after {}}} {
 	if {[lindex $cmd 0] eq {git}} {
-		set fd_f [eval git_read --stderr [lrange $cmd 1 end]]
+		set fd_f [git_read [lrange $cmd 1 end] [list 2>@1]]
 	} else {
-		lappend cmd 2>@1
-		set fd_f [_open_stdout_stderr $cmd]
+		set fd_f [safe_open_command $cmd [list 2>@1]]
 	}
 	fconfigure $fd_f -blocking 0 -translation binary
 	fileevent $fd_f readable [cb _read $fd_f $after]

git-gui/lib/console.tcl

@@ -3,7 +3,7 @@
 
 proc do_stats {} {
 	global use_ttk NS
-	set fd [git_read count-objects -v]
+	set fd [git_read [list count-objects -v]]
 	while {[gets $fd line] > 0} {
 		if {[regexp {^([^:]+): (\d+)$} $line _ name value]} {
 			set stats($name) $value