752090b963
Daniel Stenberg
2025-10-07
Subject
examples/synctime: make the sscanf not overflow the local buffer
Binary
No binary (build failed)
Architecture & Compiler Flags
—
Build Log
(log yok)
Commit Diff GitHub →
docs/examples/synctime.c+21 -39
| @@ -55,20 +55,6 @@ | |
| * Usage: | |
| * This software synchronises your computer clock only when you issue | |
| * it with --synctime. By default, it only display the webserver's clock. | |
| - | * |
| - | * Written by: Frank (contributed to libcurl) |
| - | * |
| - | * THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND, |
| - | * EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY |
| - | * WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. |
| - | * |
| - | * IN NO EVENT SHALL THE AUTHOR OF THIS SOFTWARE BE LIABLE FOR |
| - | * ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND, |
| - | * OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, |
| - | * WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF |
| - | * LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE |
| - | * OF THIS SOFTWARE. |
| - | * |
| */ | |
| #include <stdio.h> | |
| @@ -147,43 +133,39 @@ static size_t SyncTime_CURL_WriteHeader(void *ptr, size_t size, size_t nmemb, | |
| (void)stream; | |
| if(ShowAllHeader == 1) | |
| - | fprintf(stderr, "%s", (char *)(ptr)); |
| + | fprintf(stderr, "%.*s", (int)nmemb, (char *)ptr); |
| - | if(strncmp((char *)(ptr), "Date:", 5) == 0) { |
| + | if(strncmp((char *)ptr, "Date:", 5) == 0) { |
| if(ShowAllHeader == 0) | |
| - | fprintf(stderr, "HTTP Server. %s", (char *)(ptr)); |
| + | fprintf(stderr, "HTTP Server. %.*s", (int)nmemb, (char *)ptr); |
| if(AutoSyncTime == 1) { | |
| + | int RetVal; |
| *TmpStr1 = 0; | |
| *TmpStr2 = 0; | |
| - | if(strlen((char *)(ptr)) > 50) /* Can prevent buffer overflow to |
| - | TmpStr1 & 2? */ |
| - | AutoSyncTime = 0; |
| - | else { |
| - | int RetVal = sscanf((char *)(ptr), "Date: %25s %hu %s %hu %hu:%hu:%hu", |
| - | TmpStr1, &SYSTime.wDay, TmpStr2, &SYSTime.wYear, |
| - | &SYSTime.wHour, &SYSTime.wMinute, |
| - | &SYSTime.wSecond); |
| - | |
| - | if(RetVal == 7) { |
| - | int i; |
| - | SYSTime.wMilliseconds = 500; /* adjust to midpoint, 0.5 sec */ |
| - | for(i = 0; i < 12; i++) { |
| - | if(strcmp(MthStr[i], TmpStr2) == 0) { |
| - | SYSTime.wMonth = (WORD)(i + 1); |
| - | break; |
| - | } |
| + | RetVal = sscanf((char *)ptr, "Date: %25s %hu %25s %hu %hu:%hu:%hu", |
| + | TmpStr1, &SYSTime.wDay, TmpStr2, &SYSTime.wYear, |
| + | &SYSTime.wHour, &SYSTime.wMinute, |
| + | &SYSTime.wSecond); |
| + | |
| + | if(RetVal == 7) { |
| + | int i; |
| + | SYSTime.wMilliseconds = 500; /* adjust to midpoint, 0.5 sec */ |
| + | for(i = 0; i < 12; i++) { |
| + | if(strcmp(MthStr[i], TmpStr2) == 0) { |
| + | SYSTime.wMonth = (WORD)(i + 1); |
| + | break; |
| } | |
| - | AutoSyncTime = 3; /* Computer clock is adjusted */ |
| - | } |
| - | else { |
| - | AutoSyncTime = 0; /* Error in sscanf() fields conversion */ |
| } | |
| + | AutoSyncTime = 3; /* Computer clock is adjusted */ |
| + | } |
| + | else { |
| + | AutoSyncTime = 0; /* Error in sscanf() fields conversion */ |
| } | |
| } | |
| } | |
| - | if(strncmp((char *)(ptr), "X-Cache: HIT", 12) == 0) { |
| + | if(strncmp((char *)ptr, "X-Cache: HIT", 12) == 0) { |
| fprintf(stderr, "ERROR: HTTP Server data is cached." | |
| " Server Date is no longer valid.\n"); | |
| AutoSyncTime = 0; | |