[Bug analyzer/94639] New: false-positive uninitialized value on fixed sized array

[cgzones at googlemail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94639

Bug ID: 94639
   Summary: false-positive uninitialized value on fixed sized
array
   Product: gcc
   Version: unknown
Status: UNCONFIRMED
  Severity: normal
  Priority: P3
 Component: analyzer
  Assignee: dmalcolm at gcc dot gnu.org
  Reporter: cgzones at googlemail dot com
  Target Milestone: ---

Minimized code snippet:

```
#include 

void validatedatetime(const char *str)
{
const char *templates[] = {"-dd-dd dd:dd", "-dd-dd"};

size_t len = strlen(str);

for (unsigned t = 0; t < 2; t++) {
if (len != strlen(templates[t])) {
continue;
}
}
}
```

Original code:
https://github.com/vergoh/vnstat/blob/f98c27eaba27ebda703737f8a5539a77b891561e/src/misc.c#L357

GCC analyzer output:
```
$ gcc-10 -c -Wall -Wextra -fanalyzer fixed-array.c 
fixed-array.c: In function ‘validatedatetime’:
fixed-array.c:10:28: warning: use of uninitialized value ‘’ [CWE-457]
[-Wanalyzer-use-of-uninitialized-value]
   10 | if (len != strlen(templates[t])) {
  |^~~~
  ‘validatedatetime’: events 1-7
|
|9 | for (unsigned t = 0; t < 2; t++) {
|  | ^~~ ~~~
|  | ||
|  | |(4) ...to here
|  | (1) following ‘true’ branch (when ‘t <= 1’)...
|  | (5) following ‘true’ branch (when ‘t <= 1’)...
|   10 | if (len != strlen(templates[t])) {
|  |~   
|  ||   |
|  ||   (2) ...to here
|  ||   (6) ...to here
|  ||   (7) use of uninitialized value
‘’ here
|  |(3) following ‘false’ branch...
|
```

GCC version:
```
gcc-10 (Debian 10-20200411-1) 10.0.1 20200411 (experimental) [master revision
bb87d5cc77d:75961caccb7:f883c46b4877f637e0fa5025b4d6b5c9040ec566]
```

[Bug analyzer/94640] New: false-positive leaking FILE pointer assigned to function passed pointer

[cgzones at googlemail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94640

Bug ID: 94640
   Summary: false-positive leaking FILE pointer assigned to
function passed pointer
   Product: gcc
   Version: unknown
Status: UNCONFIRMED
  Severity: normal
  Priority: P3
 Component: analyzer
  Assignee: dmalcolm at gcc dot gnu.org
  Reporter: cgzones at googlemail dot com
  Target Milestone: ---

Minimized code snippet:
```
#include 

int debug;

int opencfgfile(const char *cfgfile, FILE **fd)
{
if (cfgfile[0] != '\0') {

if ((*fd = fopen(cfgfile, "r")) != NULL) {
if (debug)   // <-- this seems to trigger the fp
printf("Config file: --config\n");
}

}

return 2;
}
```

Original code:
https://github.com/vergoh/vnstat/blob/f98c27eaba27ebda703737f8a5539a77b891561e/src/cfg.c#L364

GCC analyzer output:
```
$ gcc-10 -c -Wall -Wextra -fanalyzer return_filepointer.c
return_filepointer.c: In function ‘opencfgfile’:
return_filepointer.c:10:8: warning: leak of FILE ‘’ [CWE-775]
[-Wanalyzer-file-leak]
   10 |if (debug)
  |^
  ‘opencfgfile’: events 1-7
|
|7 | if (cfgfile[0] != '\0') {
|  |^
|  ||
|  |(1) following ‘true’ branch...
|8 | 
|9 | if ((*fd = fopen(cfgfile, "r")) != NULL) {
|  |~   ~~~
|  ||   |
|  ||   (2) ...to here
|  ||   (3) opened here
|  |(4) assuming ‘’ is non-NULL
|  |(5) following ‘true’ branch...
|   10 |if (debug)
|  |~
|  ||
|  |(6) ...to here
|  |(7) ‘’ leaks here; was opened at (3)
|
```

GCC version:
```
gcc-10 (Debian 10-20200411-1) 10.0.1 20200411 (experimental) [master revision
bb87d5cc77d:75961caccb7:f883c46b4877f637e0fa5025b4d6b5c9040ec566]
```

[Bug lto/115234] New: Wnull-dereference false-positive on address of local variable

[cgzones at googlemail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115234

Bug ID: 115234
   Summary: Wnull-dereference false-positive on address of local
variable
   Product: gcc
   Version: 14.1.0
Status: UNCONFIRMED
  Severity: normal
  Priority: P3
 Component: lto
  Assignee: unassigned at gcc dot gnu.org
  Reporter: cgzones at googlemail dot com
  Target Milestone: ---

$ gcc-14 --version
gcc-14 (Debian 14.1.0-1) 14.1.0

Reproducer:

git clone --depth 1 --branch 3.7-rc1
https://github.com/seLinuxProject/selinux.git

cd selinux/

make CC='gcc-14 -flto=auto' DESTDIR=/tmp/selinux_destdir SUBDIRS='libsepol
checkpolicy' -j"$(nproc)" install

```
In function ‘sepol_context_from_string’,
inlined from ‘context_from_string’ at ../libsepol/src/context.c:315:6,
inlined from ‘sepol_context_to_sid’ at ../libsepol/src/services.c:1300:6:
../libsepol/src/context_record.c:206:22: error: potential null pointer
dereference [-Werror=null-dereference]
  206 | *con = NULL;
  |  ^
```

context_from_string():

298: sepol_context_t *ctx_record = NULL;
315: if (sepol_context_from_string(handle, con_cpy, &ctx_record) < 0)

sepol_context_from_string():

198: int sepol_context_from_string(sepol_handle_t * handle,
199:   const char *str, sepol_context_t ** con)
206: *con = NULL;