From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 7920) id EE2333858C62; Thu, 8 Jun 2023 09:50:55 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org EE2333858C62 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1686217855; bh=5caCAR5kiH5KxVjIMuMoM07J6YjxwsXA33me5+gzrm8=; h=From:To:Subject:Date:From; b=B5PcoB4stxUKXmTfrfkIqrQnvsDmMqZCvr7NbBd3MScDlGtqhq1UkRdwpTgSL6cF+ Z1L/6C0SRPlgGJH9fHKmze/moRx50rW6tCpF/kG9JGYx2301ejOPdRHcsH7BuD5C54 OIZobWKP7wnYNDegaXPhIrfrCiy6iMVV4bum7x2Q= MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="utf-8" From: Benjamin Priour To: gcc-cvs@gcc.gnu.org Subject: [gcc r14-1632] analyzer: Standalone OOB-warning [PR109437, PR109439] X-Act-Checkin: gcc X-Git-Author: Benjamin Priour X-Git-Refname: refs/heads/trunk X-Git-Oldrev: fcbef8e431c246c1f584537a08d58fcd5c5a1831 X-Git-Newrev: 9589a46ddadc8b93c224c3f84fa94746c04596bf Message-Id: <20230608095055.EE2333858C62@sourceware.org> Date: Thu, 8 Jun 2023 09:50:55 +0000 (GMT) List-Id: https://gcc.gnu.org/g:9589a46ddadc8b93c224c3f84fa94746c04596bf commit r14-1632-g9589a46ddadc8b93c224c3f84fa94746c04596bf Author: Benjamin Priour Date: Thu Jun 8 11:38:08 2023 +0200 analyzer: Standalone OOB-warning [PR109437, PR109439] This patch enhances -Wanalyzer-out-of-bounds that is no longer paired with a -Wanalyzer-use-of-uninitialized-value on out-of-bounds-read. This also fixes PR analyzer/109437. Before there could always be at most one OOB-read warning per frame because -Wanalyzer-use-of-uninitialized-value always terminates the analysis path. PR 109439 gcc/analyzer/ChangeLog: * bounds-checking.cc (region_model::check_symbolic_bounds): Returns whether the BASE_REG region access was OOB. (region_model::check_region_bounds): Likewise. * region-model.cc (region_model::get_store_value): Creates an unknown svalue on OOB-read access to REG. (region_model::check_region_access): Returns whether an unknown svalue needs be created. (region_model::check_region_for_read): Passes check_region_access return value. * region-model.h: Update prior function definitions. gcc/testsuite/ChangeLog: * gcc.dg/analyzer/out-of-bounds-2.c: Cleaned test for uninitialized-value warning * gcc.dg/analyzer/out-of-bounds-5.c: Likewise. * gcc.dg/analyzer/pr101962.c: Likewise. * gcc.dg/analyzer/realloc-5.c: Likewise. * gcc.dg/analyzer/pr109439.c: New test. Diff: --- gcc/analyzer/bounds-checking.cc | 28 +++++++++++++++++-------- gcc/analyzer/region-model.cc | 22 ++++++++++++------- gcc/analyzer/region-model.h | 8 +++---- gcc/testsuite/gcc.dg/analyzer/out-of-bounds-2.c | 1 - gcc/testsuite/gcc.dg/analyzer/out-of-bounds-5.c | 2 -- gcc/testsuite/gcc.dg/analyzer/pr101962.c | 1 - gcc/testsuite/gcc.dg/analyzer/pr109439.c | 12 +++++++++++ gcc/testsuite/gcc.dg/analyzer/realloc-5.c | 1 - 8 files changed, 49 insertions(+), 26 deletions(-) diff --git a/gcc/analyzer/bounds-checking.cc b/gcc/analyzer/bounds-checking.cc index 3bf542a8eba..a5692cf9319 100644 --- a/gcc/analyzer/bounds-checking.cc +++ b/gcc/analyzer/bounds-checking.cc @@ -767,9 +767,10 @@ public: } }; -/* Check whether an access is past the end of the BASE_REG. */ +/* Check whether an access is past the end of the BASE_REG. + Return TRUE if the access was valid, FALSE otherwise. */ -void +bool region_model::check_symbolic_bounds (const region *base_reg, const svalue *sym_byte_offset, const svalue *num_bytes_sval, @@ -800,6 +801,7 @@ region_model::check_symbolic_bounds (const region *base_reg, offset_tree, num_bytes_tree, capacity_tree)); + return false; break; case DIR_WRITE: ctxt->warn (make_unique (base_reg, @@ -807,9 +809,11 @@ region_model::check_symbolic_bounds (const region *base_reg, offset_tree, num_bytes_tree, capacity_tree)); + return false; break; } } + return true; } static tree @@ -822,9 +826,10 @@ maybe_get_integer_cst_tree (const svalue *sval) return NULL_TREE; } -/* May complain when the access on REG is out-of-bounds. */ +/* May complain when the access on REG is out-of-bounds. + Return TRUE if the access was valid, FALSE otherwise. */ -void +bool region_model::check_region_bounds (const region *reg, enum access_direction dir, region_model_context *ctxt) const @@ -839,14 +844,14 @@ region_model::check_region_bounds (const region *reg, (e.g. because the analyzer did not see previous offsets on the latter, it might think that a negative access is before the buffer). */ if (base_reg->symbolic_p ()) - return; + return true; /* Find out how many bytes were accessed. */ const svalue *num_bytes_sval = reg->get_byte_size_sval (m_mgr); tree num_bytes_tree = maybe_get_integer_cst_tree (num_bytes_sval); /* Bail out if 0 bytes are accessed. */ if (num_bytes_tree && zerop (num_bytes_tree)) - return; + return true; /* Get the capacity of the buffer. */ const svalue *capacity = get_capacity (base_reg); @@ -877,13 +882,13 @@ region_model::check_region_bounds (const region *reg, } else byte_offset_sval = reg_offset.get_symbolic_byte_offset (); - check_symbolic_bounds (base_reg, byte_offset_sval, num_bytes_sval, + return check_symbolic_bounds (base_reg, byte_offset_sval, num_bytes_sval, capacity, dir, ctxt); - return; } /* Otherwise continue to check with concrete values. */ byte_range out (0, 0); + bool oob_safe = true; /* NUM_BYTES_TREE should always be interpreted as unsigned. */ byte_offset_t num_bytes_unsigned = wi::to_offset (num_bytes_tree); byte_range read_bytes (offset, num_bytes_unsigned); @@ -899,10 +904,12 @@ region_model::check_region_bounds (const region *reg, case DIR_READ: ctxt->warn (make_unique (reg, diag_arg, out)); + oob_safe = false; break; case DIR_WRITE: ctxt->warn (make_unique (reg, diag_arg, out)); + oob_safe = false; break; } } @@ -911,7 +918,7 @@ region_model::check_region_bounds (const region *reg, do a symbolic check here because the inequality check does not reason whether constants are greater than symbolic values. */ if (!cst_capacity_tree) - return; + return oob_safe; byte_range buffer (0, wi::to_offset (cst_capacity_tree)); /* If READ_BYTES exceeds BUFFER, we do have an overflow. */ @@ -929,13 +936,16 @@ region_model::check_region_bounds (const region *reg, case DIR_READ: ctxt->warn (make_unique (reg, diag_arg, out, byte_bound)); + oob_safe = false; break; case DIR_WRITE: ctxt->warn (make_unique (reg, diag_arg, out, byte_bound)); + oob_safe = false; break; } } + return oob_safe; } } // namespace ana diff --git a/gcc/analyzer/region-model.cc b/gcc/analyzer/region-model.cc index 3bb3df2f063..fb96cd54940 100644 --- a/gcc/analyzer/region-model.cc +++ b/gcc/analyzer/region-model.cc @@ -2396,7 +2396,8 @@ region_model::get_store_value (const region *reg, if (reg->empty_p ()) return m_mgr->get_or_create_unknown_svalue (reg->get_type ()); - check_region_for_read (reg, ctxt); + if (check_region_for_read (reg, ctxt)) + return m_mgr->get_or_create_unknown_svalue(reg->get_type()); /* Special-case: handle var_decls in the constant pool. */ if (const decl_region *decl_reg = reg->dyn_cast_decl_region ()) @@ -2802,19 +2803,22 @@ region_model::get_string_size (const region *reg) const } /* If CTXT is non-NULL, use it to warn about any problems accessing REG, - using DIR to determine if this access is a read or write. */ + using DIR to determine if this access is a read or write. + Return TRUE if an UNKNOWN_SVALUE needs be created. */ -void +bool region_model::check_region_access (const region *reg, enum access_direction dir, region_model_context *ctxt) const { /* Fail gracefully if CTXT is NULL. */ if (!ctxt) - return; + return false; + bool need_unknown_sval = false; check_region_for_taint (reg, dir, ctxt); - check_region_bounds (reg, dir, ctxt); + if (!check_region_bounds (reg, dir, ctxt)) + need_unknown_sval = true; switch (dir) { @@ -2827,6 +2831,7 @@ region_model::check_region_access (const region *reg, check_for_writable_region (reg, ctxt); break; } + return need_unknown_sval; } /* If CTXT is non-NULL, use it to warn about any problems writing to REG. */ @@ -2838,13 +2843,14 @@ region_model::check_region_for_write (const region *dest_reg, check_region_access (dest_reg, DIR_WRITE, ctxt); } -/* If CTXT is non-NULL, use it to warn about any problems reading from REG. */ +/* If CTXT is non-NULL, use it to warn about any problems reading from REG. + Returns TRUE if an unknown svalue needs be created. */ -void +bool region_model::check_region_for_read (const region *src_reg, region_model_context *ctxt) const { - check_region_access (src_reg, DIR_READ, ctxt); + return check_region_access (src_reg, DIR_READ, ctxt); } /* Concrete subclass for casts of pointers that lead to trailing bytes. */ diff --git a/gcc/analyzer/region-model.h b/gcc/analyzer/region-model.h index fe3db0b0c98..12f84b20463 100644 --- a/gcc/analyzer/region-model.h +++ b/gcc/analyzer/region-model.h @@ -553,22 +553,22 @@ private: void check_for_writable_region (const region* dest_reg, region_model_context *ctxt) const; - void check_region_access (const region *reg, + bool check_region_access (const region *reg, enum access_direction dir, region_model_context *ctxt) const; - void check_region_for_read (const region *src_reg, + bool check_region_for_read (const region *src_reg, region_model_context *ctxt) const; void check_region_size (const region *lhs_reg, const svalue *rhs_sval, region_model_context *ctxt) const; /* Implemented in bounds-checking.cc */ - void check_symbolic_bounds (const region *base_reg, + bool check_symbolic_bounds (const region *base_reg, const svalue *sym_byte_offset, const svalue *num_bytes_sval, const svalue *capacity, enum access_direction dir, region_model_context *ctxt) const; - void check_region_bounds (const region *reg, enum access_direction dir, + bool check_region_bounds (const region *reg, enum access_direction dir, region_model_context *ctxt) const; void check_call_args (const call_details &cd) const; diff --git a/gcc/testsuite/gcc.dg/analyzer/out-of-bounds-2.c b/gcc/testsuite/gcc.dg/analyzer/out-of-bounds-2.c index 1330090f348..336f624441c 100644 --- a/gcc/testsuite/gcc.dg/analyzer/out-of-bounds-2.c +++ b/gcc/testsuite/gcc.dg/analyzer/out-of-bounds-2.c @@ -82,5 +82,4 @@ void test5 (void) /* { dg-warning "heap-based buffer over-read" "bounds warning" { target *-*-* } test5 } */ /* { dg-message "read of 4 bytes from after the end of the region" "num bad bytes note" { target *-*-* } test5 } */ - /* { dg-warning "use of uninitialized value" "uninit warning" { target *-*-* } test5 } */ } diff --git a/gcc/testsuite/gcc.dg/analyzer/out-of-bounds-5.c b/gcc/testsuite/gcc.dg/analyzer/out-of-bounds-5.c index 2a61d8ca236..568f9cad199 100644 --- a/gcc/testsuite/gcc.dg/analyzer/out-of-bounds-5.c +++ b/gcc/testsuite/gcc.dg/analyzer/out-of-bounds-5.c @@ -68,7 +68,6 @@ void test8 (size_t size, size_t offset) char dst[size]; memcpy (dst, src, size + offset); /* { dg-line test8 } */ /* { dg-warning "over-read" "warning" { target *-*-* } test8 } */ - /* { dg-warning "use of uninitialized value" "warning" { target *-*-* } test8 } */ /* { dg-warning "overflow" "warning" { target *-*-* } test8 } */ } @@ -78,7 +77,6 @@ void test9 (size_t size, size_t offset) int32_t dst[size]; memcpy (dst, src, 4 * size + 1); /* { dg-line test9 } */ /* { dg-warning "over-read" "warning" { target *-*-* } test9 } */ - /* { dg-warning "use of uninitialized value" "warning" { target *-*-* } test9 } */ /* { dg-warning "overflow" "warning" { target *-*-* } test9 } */ } diff --git a/gcc/testsuite/gcc.dg/analyzer/pr101962.c b/gcc/testsuite/gcc.dg/analyzer/pr101962.c index 08c0aba5cbf..b878aad9cf1 100644 --- a/gcc/testsuite/gcc.dg/analyzer/pr101962.c +++ b/gcc/testsuite/gcc.dg/analyzer/pr101962.c @@ -24,7 +24,6 @@ test_1 (void) __analyzer_eval (a != NULL); /* { dg-warning "TRUE" } */ return *a; /* { dg-line test_1 } */ - /* { dg-warning "use of uninitialized value '\\*a'" "warning" { target *-*-* } test_1 } */ /* { dg-warning "stack-based buffer over-read" "warning" { target *-*-* } test_1 } */ } diff --git a/gcc/testsuite/gcc.dg/analyzer/pr109439.c b/gcc/testsuite/gcc.dg/analyzer/pr109439.c new file mode 100644 index 00000000000..01c87cf171c --- /dev/null +++ b/gcc/testsuite/gcc.dg/analyzer/pr109439.c @@ -0,0 +1,12 @@ +int would_like_only_oob (int i) +{ + int arr[] = {1,2,3,4,5,6,7}; + arr[10] = 9; /* { dg-warning "stack-based buffer overflow" } */ + arr[11] = 15; /* { dg-warning "stack-based buffer overflow" } */ + int y1 = arr[9]; /* { dg-warning "stack-based buffer over-read" } */ + /* { dg-bogus "use of uninitialized value" "" { target *-*-* } .-1 } */ + + arr[18] = 15; /* { dg-warning "stack-based buffer overflow" } */ + + return y1; +} diff --git a/gcc/testsuite/gcc.dg/analyzer/realloc-5.c b/gcc/testsuite/gcc.dg/analyzer/realloc-5.c index 137e05b87aa..f65f2c6ca25 100644 --- a/gcc/testsuite/gcc.dg/analyzer/realloc-5.c +++ b/gcc/testsuite/gcc.dg/analyzer/realloc-5.c @@ -40,7 +40,6 @@ void test_1 () /* { dg-warning "UNKNOWN" "warning" { target *-*-* } eval } */ /* { dg-warning "heap-based buffer over-read" "warning" { target *-*-* } eval } */ - /* { dg-warning "use of uninitialized value" "warning" { target *-*-* } eval } */ } free (q);