From a481d4378cc503ac5646d44533a05fcac569a93f Mon Sep 17 00:00:00 2001 From: Derrick Stolee Date: Thu, 16 Dec 2021 16:13:40 +0000 Subject: [PATCH 1/3] sparse-checkout: fix segfault on malformed patterns Then core.sparseCheckoutCone is enabled, the sparse-checkout patterns are used to populate two hashsets that accelerate pattern matching. If the user modifies the sparse-checkout file outside of the 'sparse-checkout' builtin, then strange patterns can happen, triggering some error checks. One of these error checks is possible to hit when some special characters exist in a line. A warning message is correctly written to stderr, but then there is additional logic that attempts to remove the line from the hashset and free the data. This leads to a segfault in the 'git sparse-checkout list' command because it iterates over the contents of the hashset, which is now invalid. The fix here is to stop trying to remove from the hashset. In addition, we disable cone mode sparse-checkout because of the malformed data. This results in the pattern-matching working with a possibly-slower algorithm, but using the patterns as they are in the sparse-checkout file. This also changes the behavior of commands such as 'git sparse-checkout list' because the output patterns will be the contents of the sparse-checkout file instead of the list of directories. This is an existing behavior for other types of bad patterns. Add a test that triggers the segfault without the code change. Reported-by: John Burnett Reviewed-by: Elijah Newren Signed-off-by: Derrick Stolee Signed-off-by: Junio C Hamano --- dir.c | 4 +--- t/t1091-sparse-checkout-builtin.sh | 21 +++++++++++++++++++++ 2 files changed, 22 insertions(+), 3 deletions(-) diff --git a/dir.c b/dir.c index 5aa6fbad0b76ad..7e72958d51dabb 100644 --- a/dir.c +++ b/dir.c @@ -819,9 +819,7 @@ static void add_pattern_to_hashsets(struct pattern_list *pl, struct path_pattern /* we already included this at the parent level */ warning(_("your sparse-checkout file may have issues: pattern '%s' is repeated"), given->pattern); - hashmap_remove(&pl->parent_hashmap, &translated->ent, &data); - free(data); - free(translated); + goto clear_hashmaps; } return; diff --git a/t/t1091-sparse-checkout-builtin.sh b/t/t1091-sparse-checkout-builtin.sh index 272ba1b566b3ea..3921ea80138bf5 100755 --- a/t/t1091-sparse-checkout-builtin.sh +++ b/t/t1091-sparse-checkout-builtin.sh @@ -708,4 +708,25 @@ test_expect_success 'cone mode clears ignored subdirectories' ' test_cmp expect out ' +test_expect_success 'malformed cone-mode patterns' ' + git -C repo sparse-checkout init --cone && + mkdir -p repo/foo/bar && + touch repo/foo/bar/x repo/foo/y && + cat >repo/.git/info/sparse-checkout <<-\EOF && + /* + !/*/ + /foo/ + !/foo/*/ + /foo/\*/ + EOF + + # Listing the patterns will notice the duplicate pattern and + # emit a warning. It will list the patterns directly instead + # of using the cone-mode translation to a set of directories. + git -C repo sparse-checkout list >actual 2>err && + test_cmp repo/.git/info/sparse-checkout actual && + grep "warning: your sparse-checkout file may have issues: pattern .* is repeated" err && + grep "warning: disabling cone pattern matching" err +' + test_done From 391c3a1020127c9dbf6995effe2f84d3443292d8 Mon Sep 17 00:00:00 2001 From: Derrick Stolee Date: Thu, 16 Dec 2021 16:13:41 +0000 Subject: [PATCH 2/3] sparse-checkout: fix OOM error with mixed patterns Add a test to t1091-sparse-checkout-builtin.sh that would result in an infinite loop and out-of-memory error before this change. The issue relies on having non-cone-mode patterns while trying to modify the patterns in cone-mode. The fix is simple, allowing us to break from the loop when the input path does not contain a slash, as the "dir" pattern we added does not. This is only a fix to the critical out-of-memory error. A better response to such a strange state will follow in a later change. Reported-by: Calbabreaker Helped-by: Taylor Blau Reviewed-by: Elijah Newren Signed-off-by: Derrick Stolee Signed-off-by: Junio C Hamano --- builtin/sparse-checkout.c | 2 +- t/t1091-sparse-checkout-builtin.sh | 11 +++++++++++ 2 files changed, 12 insertions(+), 1 deletion(-) diff --git a/builtin/sparse-checkout.c b/builtin/sparse-checkout.c index d0f5c4702be69d..9ccdcde9832e93 100644 --- a/builtin/sparse-checkout.c +++ b/builtin/sparse-checkout.c @@ -483,7 +483,7 @@ static void insert_recursive_pattern(struct pattern_list *pl, struct strbuf *pat char *oldpattern = e->pattern; size_t newlen; - if (slash == e->pattern) + if (!slash || slash == e->pattern) break; newlen = slash - e->pattern; diff --git a/t/t1091-sparse-checkout-builtin.sh b/t/t1091-sparse-checkout-builtin.sh index 3921ea80138bf5..1f877ced0c887c 100755 --- a/t/t1091-sparse-checkout-builtin.sh +++ b/t/t1091-sparse-checkout-builtin.sh @@ -103,6 +103,17 @@ test_expect_success 'clone --sparse' ' check_files clone a ' +test_expect_success 'switching to cone mode with non-cone mode patterns' ' + git init bad-patterns && + ( + cd bad-patterns && + git sparse-checkout init && + git sparse-checkout add dir && + git config core.sparseCheckoutCone true && + git sparse-checkout add dir + ) +' + test_expect_success 'interaction with clone --no-checkout (unborn index)' ' git clone --no-checkout "file://$(pwd)/repo" clone_no_checkout && git -C clone_no_checkout sparse-checkout init --cone && From a3eca5844526fd6111e7a1e8bdfa9813673a6f23 Mon Sep 17 00:00:00 2001 From: Derrick Stolee Date: Thu, 16 Dec 2021 16:13:42 +0000 Subject: [PATCH 3/3] sparse-checkout: refuse to add to bad patterns When in cone mode sparse-checkout, it is unclear how 'git sparse-checkout add ...' should behave if the existing sparse-checkout file does not match the cone mode patterns. Change the behavior to fail with an error message about the existing patterns. Also, all cone mode patterns start with a '/' character, so add that restriction. This is necessary for our example test 'cone mode: warn on bad pattern', but also requires modifying the example sparse-checkout file we use to test the warnings related to recognizing cone mode patterns. This error checking would cause a failure further down the test script because of a test that adds non-cone mode patterns without cleaning them up. Perform that cleanup as part of the test now. Reviewed-by: Elijah Newren Signed-off-by: Derrick Stolee Signed-off-by: Junio C Hamano --- builtin/sparse-checkout.c | 3 +++ dir.c | 2 +- t/t1091-sparse-checkout-builtin.sh | 7 +++++-- 3 files changed, 9 insertions(+), 3 deletions(-) diff --git a/builtin/sparse-checkout.c b/builtin/sparse-checkout.c index 9ccdcde9832e93..6580075a63181d 100644 --- a/builtin/sparse-checkout.c +++ b/builtin/sparse-checkout.c @@ -598,6 +598,9 @@ static void add_patterns_cone_mode(int argc, const char **argv, die(_("unable to load existing sparse-checkout patterns")); free(sparse_filename); + if (!existing.use_cone_patterns) + die(_("existing sparse-checkout patterns do not use cone mode")); + hashmap_for_each_entry(&existing.recursive_hashmap, &iter, pe, ent) { if (!hashmap_contains_parent(&pl->recursive_hashmap, pe->pattern, &buffer) || diff --git a/dir.c b/dir.c index 7e72958d51dabb..eca75e89213ec8 100644 --- a/dir.c +++ b/dir.c @@ -727,7 +727,7 @@ static void add_pattern_to_hashsets(struct pattern_list *pl, struct path_pattern } if (given->patternlen < 2 || - *given->pattern == '*' || + *given->pattern != '/' || strstr(given->pattern, "**")) { /* Not a cone pattern. */ warning(_("unrecognized pattern: '%s'"), given->pattern); diff --git a/t/t1091-sparse-checkout-builtin.sh b/t/t1091-sparse-checkout-builtin.sh index 1f877ced0c887c..34b97fd3ee0857 100755 --- a/t/t1091-sparse-checkout-builtin.sh +++ b/t/t1091-sparse-checkout-builtin.sh @@ -110,7 +110,8 @@ test_expect_success 'switching to cone mode with non-cone mode patterns' ' git sparse-checkout init && git sparse-checkout add dir && git config core.sparseCheckoutCone true && - git sparse-checkout add dir + test_must_fail git sparse-checkout add dir 2>err && + grep "existing sparse-checkout patterns do not use cone mode" err ) ' @@ -176,12 +177,14 @@ test_expect_success 'set sparse-checkout using --stdin' ' ' test_expect_success 'add to sparse-checkout' ' - cat repo/.git/info/sparse-checkout >expect && + cat repo/.git/info/sparse-checkout >old && + test_when_finished cp old repo/.git/info/sparse-checkout && cat >add <<-\EOF && pattern1 /folder1/ pattern2 EOF + cat old >expect && cat add >>expect && git -C repo sparse-checkout add --stdin actual &&