... by introducing a printf() function that appends directly into a
dynbuf: Curl_dyn_vprintf(). This avoids the mandatory extra malloc so if
the buffer is already big enough it can just printf directly into it.
Since this less-malloc version requires tthe use of a library internal
printf function, we only provide this version when building libcurl and
not for the dynbuf code that is used when building the curl tool.
Closes#5998
Stack overflows can occur with precisions for integers and floats.
Proof of concepts:
- curl_mprintf("%d, %.*1$d", 500, 1);
- curl_mprintf("%d, %+0500.*1$f", 500, 1);
Ideally, compile with -fsanitize=address which makes this undefined
behavior a bit more defined for debug purposes.
The format strings are valid. The overflows occur due to invalid
arguments. If these arguments are variables with contents controlled
by an attacker, the function's stack can be corrupted.
Also see CVE-2016-9586 which partially fixed the float aspect.
Signed-off-by: Tobias Stoeckmann <tobias@stoeckmann.org>
Closes https://github.com/curl/curl/pull/5722
Verify that specified parameters are in range. If parameters are too
large, fail early on and avoid out of boundary accesses.
Also do not read behind boundaries of illegal format strings.
These are defensive measures since it is expected that format strings
are well-formed. Format strings should not be modifiable by user
input due to possible generic format string attacks.
Closes https://github.com/curl/curl/pull/5722
- Stick to a single unified way to use structs
- Make checksrc complain on 'typedef struct {'
- Allow them in tests, public headers and examples
- Let MD4_CTX, MD5_CTX, and SHA256_CTX typedefs remain as they actually
typedef different types/structs depending on build conditions.
Closes#5338
A common set of functions instead of many separate implementations for
creating buffers that can grow when appending data to them. Existing
functionality has been ported over.
In my early basic testing, the total number of allocations seem at
roughly the same amount as before, possibly a few less.
See docs/DYNBUF.md for a description of the API.
Closes#5300
- Disable warning C4127 "conditional expression is constant" globally
in curl_setup.h for when building with Microsoft's compiler.
This mainly affects building with the Visual Studio project files found
in the projects dir.
Prior to this change the cmake and winbuild build systems already
disabled 4127 globally for when building with Microsoft's compiler.
Also, 4127 was already disabled for all build systems in the limited
circumstance of the WHILE_FALSE macro which disabled the warning
specifically for while(0). This commit removes the WHILE_FALSE macro and
all other cruft in favor of disabling globally in curl_setup.
Background:
We have various macros that cause 0 or 1 to be evaluated, which would
cause warning C4127 in Visual Studio. For example this causes it:
#define Curl_resolver_asynch() 1
Full behavior is not clearly defined and inconsistent across versions.
However it is documented that since VS 2015 Update 3 Microsoft has
addressed this somewhat but not entirely, not warning on while(true) for
example.
Prior to this change some C4127 warnings occurred when I built with
Visual Studio using the generated projects in the projects dir.
Closes https://github.com/curl/curl/pull/4658
The overflow has no real world impact.
Just avoid it for "best practice".
Code change suggested by "The Infinnovation Team" and Daniel Stenberg.
Closes#3184
Fix the following warnings when building the tests by using the correct
types:
cast from 'const char *' to 'void *' drops const qualifier
[-Wcast-qual]
implicit conversion changes signedness [-Wsign-conversion]
This fixes the following clang warnings:
macro is not used [-Wunused-macros]
will never be executed [-Wunreachable-code]
Closes https://github.com/curl/curl/pull/1448
Visual C++ complained:
warning C4267: '=': conversion from 'size_t' to 'long', possible loss of data
warning C4701: potentially uninitialized local variable 'path' used
CID 1024412: Memory - illegal accesses (OVERRUN). Claimed to happen when
we run over 'workend' but the condition says <= workend and for all I
can see it should be safe. Compensating for the warning by adding a byte
margin in the buffer.
Also, removed the extra brace level indentation in the code and made it
so that 'workend' is only assigned once within the function.
Prior to this change a width arg could be erroneously output, and also
width and precision args could not be used together without crashing.
"%0*d%s", 2, 9, "foo"
Before: "092"
After: "09foo"
"%*.*s", 5, 2, "foo"
Before: crash
After: " fo"
Test 557 is updated to verify this and more
The define is not in our name space and is therefore not protected by
our API promises.
It was only really used by libcurl internals but was mostly erased from
there already in 8aabbf5 (March 2015). This is supposedly the final
death blow to that define from everywhere.
As a side-effect, making sure _MPRINTF_REPLACE is gone and not used, I
made the lib tests in tests/libtest/ use curl_printf.h for its redefine
magic and then subsequently the use of sprintf() got banned in the tests
as well (as it is in libcurl internals) and I then replaced them all
with snprintf().
In the unlikely event that any users is actually using this define and
gets sad by this change, it is very easily copied to the user's own
code.
If the precision is indeed shorter than the string, don't strlen() to
find the end because that's not how the precision operator works.
I also added a unit test for curl_msnprintf to make sure this works and
that the fix doesn't a few other basic use cases. I found a POSIX
compliance problem that I marked TODO in the unit test, and I figure we
need to add more tests in the future.
Reported-by: Török Edwin
Added support to the built-in printf() replacement functions, for these
non-ANSI extensions when compiling under Visual Studio, Borland, Watcom
and MinGW.
This fixes problems when generating libcurl source code that contains
curl_off_t variables.
When using %x, the number must be treated as unsigned as otherwise it
would get sign-extended on for example 64bit machines and do wrong
output. This problem showed when doing printf("%08x", 0xffeeddcc) on a
64bit host.
The list of unsafe functions currently consists of sprintf, vsprintf,
strcat, strncat and gets.
Subsequently, some existing code needed updating to avoid warnings on
this.
This commit renames lib/setup.h to lib/curl_setup.h and
renames lib/setup_once.h to lib/curl_setup_once.h.
Removes the need and usage of a header inclusion guard foreign
to libcurl. [1]
Removes the need and presence of an alarming notice we carried
in old setup_once.h [2]
----------------------------------------
1 - lib/setup_once.h used __SETUP_ONCE_H macro as header inclusion guard
up to commit ec691ca3 which changed this to HEADER_CURL_SETUP_ONCE_H,
this single inclusion guard is enough to ensure that inclusion of
lib/setup_once.h done from lib/setup.h is only done once.
Additionally lib/setup.h has always used __SETUP_ONCE_H macro to
protect inclusion of setup_once.h even after commit ec691ca3, this
was to avoid a circular header inclusion triggered when building a
c-ares enabled version with c-ares sources available which also has
a setup_once.h header. Commit ec691ca3 exposes the real nature of
__SETUP_ONCE_H usage in lib/setup.h, it is a header inclusion guard
foreign to libcurl belonging to c-ares's setup_once.h
The renaming this commit does, fixes the circular header inclusion,
and as such removes the need and usage of a header inclusion guard
foreign to libcurl. Macro __SETUP_ONCE_H no longer used in libcurl.
2 - Due to the circular interdependency of old lib/setup_once.h and the
c-ares setup_once.h header, old file lib/setup_once.h has carried
back from 2006 up to now days an alarming and prominent notice about
the need of keeping libcurl's and c-ares's setup_once.h in sync.
Given that this commit fixes the circular interdependency, the need
and presence of mentioned notice is removed.
All mentioned interdependencies come back from now old days when
the c-ares project lived inside a curl subdirectory. This commit
removes last traces of such fact.
This reverts renaming and usage of lib/*.h header files done
28-12-2012, reverting 2 commits:
f871de0... build: make use of 76 lib/*.h renamed files
ffd8e12... build: rename 76 lib/*.h files
This also reverts removal of redundant include guard (redundant thanks
to changes in above commits) done 2-12-2013, reverting 1 commit:
c087374... curl_setup.h: remove redundant include guard
This also reverts renaming and usage of lib/*.c source files done
3-12-2013, reverting 3 commits:
13606bb... build: make use of 93 lib/*.c renamed files
5b6e792... build: rename 93 lib/*.c files
7d83dff... build: commit 13606bbfde follow-up 1
Start of related discussion thread:
http://curl.haxx.se/mail/lib-2013-01/0012.html
Asking for confirmation on pushing this revertion commit:
http://curl.haxx.se/mail/lib-2013-01/0048.html
Confirmation summary:
http://curl.haxx.se/mail/lib-2013-01/0079.html
NOTICE: The list of 2 files that have been modified by other
intermixed commits, while renamed, and also by at least one
of the 6 commits this one reverts follows below. These 2 files
will exhibit a hole in history unless git's '--follow' option
is used when viewing logs.
lib/curl_imap.h
lib/curl_smtp.h
Just internal stuff...
Curl_safefree is now a macro defined in memdebug.h instead of a function
prototyped in url.h and implemented in url.c, so inclusion of url.h is no
longer required in order to simply use Curl_safefree.
Provide definition of macro WHILE_FALSE in setup_once.h in order to allow
other macros such as DEBUGF and DEBUGASSERT, and code using it, to compile
without 'conditional expression is constant' warnings.
The WHILE_FALSE stuff fixes 150+ MSVC compiler warnings.
Daniel Stenberg
Tobias Stoeckmann
Jay Satiro
Tim Rühsen
Marcel Raad
Sylvestre Ledru
Dan Fandrich
Steve Holme
Yang Tse
Fabian Keil