https://github.com/balazske updated
https://github.com/llvm/llvm-project/pull/71373
From 653aeb7f5b0d0f200b3f706bad770a9be643669c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bal=C3=A1zs=20K=C3=A9ri?= <balazs.k...@ericsson.com>
Date: Fri, 3 Nov 2023 09:48:18 +0100
Subject: [PATCH 1/2] [clang][analyzer] Improve StdLibraryFunctionsChecker
'readlink' modeling.
The functions 'readlink' and 'readlinkat' do return 0 only if the
'bufsize' argument is 0.
---
.../Checkers/StdLibraryFunctionsChecker.cpp | 18 +++++++++++++----
.../Analysis/std-c-library-functions-POSIX.c | 20 +++++++++++++++++++
2 files changed, 34 insertions(+), 4 deletions(-)
diff --git a/clang/lib/StaticAnalyzer/Checkers/StdLibraryFunctionsChecker.cpp
b/clang/lib/StaticAnalyzer/Checkers/StdLibraryFunctionsChecker.cpp
index 13bb9cef5e490ed..54a41b8bd7843dd 100644
--- a/clang/lib/StaticAnalyzer/Checkers/StdLibraryFunctionsChecker.cpp
+++ b/clang/lib/StaticAnalyzer/Checkers/StdLibraryFunctionsChecker.cpp
@@ -2865,9 +2865,14 @@ void StdLibraryFunctionsChecker::initFunctionSummaries(
Signature(ArgTypes{ConstCharPtrRestrictTy, CharPtrRestrictTy, SizeTy},
RetType{Ssize_tTy}),
Summary(NoEvalCall)
- .Case({ReturnValueCondition(LessThanOrEq, ArgNo(2)),
- ReturnValueCondition(WithinRange, Range(0, Ssize_tMax))},
+ .Case({ArgumentCondition(2, WithinRange, Range(1, IntMax)),
+ ReturnValueCondition(LessThanOrEq, ArgNo(2)),
+ ReturnValueCondition(WithinRange, Range(1, Ssize_tMax))},
ErrnoMustNotBeChecked, GenericSuccessMsg)
+ .Case({ArgumentCondition(2, WithinRange, SingleValue(0)),
+ ReturnValueCondition(WithinRange, SingleValue(0))},
+ ErrnoMustNotBeChecked,
+ "Assuming that argument 'bufsize' is 0")
.Case(ReturnsMinusOne, ErrnoNEZeroIrrelevant, GenericFailureMsg)
.ArgConstraint(NotNull(ArgNo(0)))
.ArgConstraint(NotNull(ArgNo(1)))
@@ -2884,9 +2889,14 @@ void StdLibraryFunctionsChecker::initFunctionSummaries(
ArgTypes{IntTy, ConstCharPtrRestrictTy, CharPtrRestrictTy, SizeTy},
RetType{Ssize_tTy}),
Summary(NoEvalCall)
- .Case({ReturnValueCondition(LessThanOrEq, ArgNo(3)),
- ReturnValueCondition(WithinRange, Range(0, Ssize_tMax))},
+ .Case({ArgumentCondition(3, WithinRange, Range(1, IntMax)),
+ ReturnValueCondition(LessThanOrEq, ArgNo(3)),
+ ReturnValueCondition(WithinRange, Range(1, Ssize_tMax))},
ErrnoMustNotBeChecked, GenericSuccessMsg)
+ .Case({ArgumentCondition(3, WithinRange, SingleValue(0)),
+ ReturnValueCondition(WithinRange, SingleValue(0))},
+ ErrnoMustNotBeChecked,
+ "Assuming that argument 'bufsize' is 0")
.Case(ReturnsMinusOne, ErrnoNEZeroIrrelevant, GenericFailureMsg)
.ArgConstraint(ValidFileDescriptorOrAtFdcwd(ArgNo(0)))
.ArgConstraint(NotNull(ArgNo(1)))
diff --git a/clang/test/Analysis/std-c-library-functions-POSIX.c
b/clang/test/Analysis/std-c-library-functions-POSIX.c
index 84ce0f21e569fb5..daa4d904c3ac5ed 100644
--- a/clang/test/Analysis/std-c-library-functions-POSIX.c
+++ b/clang/test/Analysis/std-c-library-functions-POSIX.c
@@ -205,3 +205,23 @@ void test_sendmsg(int sockfd, const struct msghdr *msg,
int flags) {
ssize_t Ret = sendmsg(sockfd, msg, flags);
clang_analyzer_eval(Ret != 0); // expected-warning{{TRUE}}
}
+
+void test_readlink_bufsize_zero(char *Buf, size_t Bufsize) {
+ ssize_t Ret = readlink("path", Buf, Bufsize);
+ if (Ret == 0)
+ clang_analyzer_eval(Bufsize == 0); // expected-warning{{TRUE}}
+ else if (Ret > 0)
+ clang_analyzer_eval(Bufsize == 0); // expected-warning{{FALSE}}
+ else
+ clang_analyzer_eval(Bufsize == 0); // expected-warning{{UNKNOWN}}
+}
+
+void test_readlinkat_bufsize_zero(int fd, char *Buf, size_t Bufsize) {
+ ssize_t Ret = readlinkat(fd, "path", Buf, Bufsize);
+ if (Ret == 0)
+ clang_analyzer_eval(Bufsize == 0); // expected-warning{{TRUE}}
+ else if (Ret > 0)
+ clang_analyzer_eval(Bufsize == 0); // expected-warning{{FALSE}}
+ else
+ clang_analyzer_eval(Bufsize == 0); // expected-warning{{UNKNOWN}}
+}
From d66440541d1fbbf50f5b750f306f79a00d3aaedc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bal=C3=A1zs=20K=C3=A9ri?= <balazs.k...@ericsson.com>
Date: Wed, 8 Nov 2023 16:17:15 +0100
Subject: [PATCH 2/2] add missing test
---
clang/test/Analysis/std-c-library-functions-path-notes.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/clang/test/Analysis/std-c-library-functions-path-notes.c
b/clang/test/Analysis/std-c-library-functions-path-notes.c
index d0957483c1391ad..4df00fe1e60646f 100644
--- a/clang/test/Analysis/std-c-library-functions-path-notes.c
+++ b/clang/test/Analysis/std-c-library-functions-path-notes.c
@@ -80,3 +80,12 @@ int test_fileno_arg_note(FILE *f1) {
// expected-note{{The 1st argument to 'dup' is < 0 but should be >= 0}} \
// expected-note{{Assuming that 'fileno' fails}}
}
+
+int test_readlink_bufsize_zero(char *Buf, size_t Bufsize) {
+ ssize_t Ret = readlink("path", Buf, Bufsize); // \
+ // expected-note{{Assuming that argument 'bufsize' is 0}} \
+ // expected-note{{'Ret' initialized here}}
+ return 1 / Ret; // \
+ // expected-warning{{Division by zero}} \
+ // expected-note{{Division by zero}}
+}
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