debuginfod: PR28034 - client-side %-escape url characters

When requesting some source files, some URL-inconvenient chars
sometimes pop up.  Example from f33 libstdc++:
/buildid/44d8485cb75512c2ca5c8f70afbd475cae30af4f/source/usr/src/debug/
gcc-10.3.1-1.fc33.x86_64/obj-x86_64-redhat-linux/x86_64-redhat-linux/
libstdc++-v3/src/c++11/../../../../../libstdc++-v3/src/c++11/
condition_variable.cc
As this URL is passed into debuginfod's handler_cb, it appears that the
+ signs are helpfully unescaped to spaces by libmicrohttpd, which
'course breaks everything.
In order to ensure the server properly parses urls such as this one,
%-escape characters on the client side so that the correct url
is preserved and properly processed on the server side.

https://sourceware.org/bugzilla/show_bug.cgi?id=28034

Signed-off-by: Noah Sanci <nsanci@redhat.com>

5 files changed, 48 insertions, 18 deletions

diff --git a/debuginfod/ChangeLog b/debuginfod/ChangeLog
index 0de17899..7709c24d 100644
--- a/debuginfod/ChangeLog
+++ b/debuginfod/ChangeLog
@@ -1,3 +1,9 @@
+2021-07-16  Noah Sanci  <nsanci@redhat.com>
+
+	PR28034
+	* debuginfod-client.c (debuginfod_query_server): % escape filename
+	so the completed url is processed properly.
+
 2021-06-28 Noah Sanci <nsanci@redhat.com>
 
 	PR25978
diff --git a/debuginfod/debuginfod-client.c b/debuginfod/debuginfod-client.c
index f12f609c..26ba1891 100644
--- a/debuginfod/debuginfod-client.c
+++ b/debuginfod/debuginfod-client.c
@@ -832,8 +832,19 @@ debuginfod_query_server (debuginfod_client *c,
         slashbuildid = "/buildid";
 
       if (filename) /* must start with / */
-        snprintf(data[i].url, PATH_MAX, "%s%s/%s/%s%s", server_url,
-                 slashbuildid, build_id_bytes, type, filename);
+        {
+          /* PR28034 escape characters in completed url to %hh format. */
+          char *escaped_string;
+          escaped_string = curl_easy_escape(data[i].handle, filename, 0);
+          if (!escaped_string)
+            {
+              rc = -ENOMEM;
+              goto out1;
+            }
+          snprintf(data[i].url, PATH_MAX, "%s%s/%s/%s%s", server_url,
+                   slashbuildid, build_id_bytes, type, escaped_string);
+          curl_free(escaped_string);
+        }
       else
         snprintf(data[i].url, PATH_MAX, "%s%s/%s/%s", server_url,
                  slashbuildid, build_id_bytes, type);
diff --git a/doc/debuginfod.8 b/doc/debuginfod.8
index d83c7cdb..f70af625 100644
--- a/doc/debuginfod.8
+++ b/doc/debuginfod.8
@@ -309,6 +309,10 @@ l l.
 \../bar/foo.c AT_comp_dir=/zoo/	/buildid/BUILDID/source/zoo//../bar/foo.c
 .TE
 
+Note: the client should %-escape characters in /SOURCE/FILE that are
+not shown as "unreserved" in section 2.3 of RFC3986. Some characters
+that will be escaped include "+", "\\", "$", "!", the 'space' character,
+and ";". RFC3986 includes a more comprehensive list of these characters.
 .SS /metrics
 
 This endpoint returns a Prometheus formatted text/plain dump of a
diff --git a/tests/ChangeLog b/tests/ChangeLog
index 51ae44eb..3be9ee48 100644
--- a/tests/ChangeLog
+++ b/tests/ChangeLog
@@ -1,3 +1,12 @@
+2021-07-16  Noah Sanci  <nsanci@redhat.com>
+
+	PR28034
+	* run-debuginfod-find.sh: Added a test ensuring files with %
+	escapable characters in their paths are accessible. The test
+	itself is changing the name of a binary known previously as prog to
+	p+r%o$g. General operations such as accessing p+r%o$g acts as the
+	test for %-escape checking.
+
 2021-07-21  Noah Sanci <nsanci@redhat.com>
 
 	* run-debuginfod-find.sh: Properly kill $PID4 by waiting for it to
diff --git a/tests/run-debuginfod-find.sh b/tests/run-debuginfod-find.sh
index b65f3580..947c1261 100755
--- a/tests/run-debuginfod-find.sh
+++ b/tests/run-debuginfod-find.sh
@@ -152,18 +152,18 @@ ps -q $PID1 -e -L -o '%p %c %a' | grep traverse
 # Compile a simple program, strip its debuginfo and save the build-id.
 # Also move the debuginfo into another directory so that elfutils
 # cannot find it without debuginfod.
-echo "int main() { return 0; }" > ${PWD}/prog.c
-tempfiles prog.c
+echo "int main() { return 0; }" > ${PWD}/p+r%o\$g.c
+tempfiles p+r%o\$g.c
 # Create a subdirectory to confound source path names
 mkdir foobar
-gcc -Wl,--build-id -g -o prog ${PWD}/foobar///./../prog.c
-testrun ${abs_top_builddir}/src/strip -g -f prog.debug ${PWD}/prog
+gcc -Wl,--build-id -g -o p+r%o\$g ${PWD}/foobar///./../p+r%o\$g.c
+testrun ${abs_top_builddir}/src/strip -g -f p+r%o\$g.debug ${PWD}/p+r%o\$g
 BUILDID=`env LD_LIBRARY_PATH=$ldpath ${abs_builddir}/../src/readelf \
-          -a prog | grep 'Build ID' | cut -d ' ' -f 7`
+          -a p+r%o\\$g | grep 'Build ID' | cut -d ' ' -f 7`
 
 wait_ready $PORT1 'thread_work_total{role="traverse"}' 1
-mv prog F
-mv prog.debug F
+mv p+r%o\$g F
+mv p+r%o\$g.debug F
 kill -USR1 $PID1
 # Wait till both files are in the index.
 wait_ready $PORT1 'thread_work_total{role="traverse"}' 2
@@ -174,7 +174,7 @@ wait_ready $PORT1 'thread_busy{role="scan"}' 0
 
 # Test whether elfutils, via the debuginfod client library dlopen hooks,
 # is able to fetch debuginfo from the local debuginfod.
-testrun ${abs_builddir}/debuginfod_build_id_find -e F/prog 1
+testrun ${abs_builddir}/debuginfod_build_id_find -e F/p+r%o\$g 1
 
 ########################################################################
 
@@ -216,22 +216,22 @@ fi
 # Test whether debuginfod-find is able to fetch those files.
 rm -rf $DEBUGINFOD_CACHE_PATH # clean it from previous tests
 filename=`testrun ${abs_top_builddir}/debuginfod/debuginfod-find debuginfo $BUILDID`
-cmp $filename F/prog.debug
+cmp $filename F/p+r%o\$g.debug
 if [ -w $filename ]; then
     echo "cache file writable, boo"
     err
 fi
 
-filename=`testrun ${abs_top_builddir}/debuginfod/debuginfod-find executable F/prog`
-cmp $filename F/prog
+filename=`testrun ${abs_top_builddir}/debuginfod/debuginfod-find executable F/p+r%o\\$g`
+cmp $filename F/p+r%o\$g
 
 # raw source filename
-filename=`testrun ${abs_top_builddir}/debuginfod/debuginfod-find source $BUILDID ${PWD}/foobar///./../prog.c`
-cmp $filename  ${PWD}/prog.c
+filename=`testrun ${abs_top_builddir}/debuginfod/debuginfod-find source $BUILDID ${PWD}/foobar///./../p+r%o\\$g.c`
+cmp $filename  ${PWD}/p+r%o\$g.c
 
 # and also the canonicalized one
-filename=`testrun ${abs_top_builddir}/debuginfod/debuginfod-find source $BUILDID ${PWD}/prog.c`
-cmp $filename  ${PWD}/prog.c
+filename=`testrun ${abs_top_builddir}/debuginfod/debuginfod-find source $BUILDID ${PWD}/p+r%o\\$g.c`
+cmp $filename  ${PWD}/p+r%o\$g.c
 
 
 ########################################################################
@@ -688,7 +688,7 @@ touch -d '1970-01-01' $DEBUGINFOD_CACHE_PATH/00000000 # old enough to guarantee
 echo 0 > $DEBUGINFOD_CACHE_PATH/cache_clean_interval_s
 echo 0 > $DEBUGINFOD_CACHE_PATH/max_unused_age_s
 
-testrun ${abs_builddir}/debuginfod_build_id_find -e F/prog 1
+testrun ${abs_builddir}/debuginfod_build_id_find -e F/p+r%o\$g 1
 
 testrun ${abs_top_builddir}/debuginfod/debuginfod-find debuginfo $BUILDID2 && false || true