File curl-CVE-2025-0725.patch of Package curl.37296

From 76f83f0db23846e254d940ec7fe141010077eb88 Mon Sep 17 00:00:00 2001
From: Daniel Stenberg <daniel@haxx.se>
Date: Fri, 24 Jan 2025 11:13:24 +0100
Subject: [PATCH] content_encoding: drop support for zlib before 1.2.0.4

zlib 1.2.0.4 was released on 10 August 2003

Closes #16079
---
 docs/INTERNALS.md      |   2 +-
 lib/content_encoding.c | 276 ++++-------------------------------------
 2 files changed, 25 insertions(+), 253 deletions(-)

Index: curl-8.0.1/docs/INTERNALS.md
===================================================================
--- curl-8.0.1.orig/docs/INTERNALS.md
+++ curl-8.0.1/docs/INTERNALS.md
@@ -20,7 +20,7 @@ versions of libs and build tools.
 
  - OpenSSL      0.9.7
  - GnuTLS       3.1.10
- - zlib         1.1.4
+ - zlib         1.2.0.4
  - libssh2      1.0
  - c-ares       1.16.0
  - libidn2      2.0.0
Index: curl-8.0.1/lib/content_encoding.c
===================================================================
--- curl-8.0.1.orig/lib/content_encoding.c
+++ curl-8.0.1/lib/content_encoding.c
@@ -60,33 +60,15 @@
 
 #ifndef CURL_DISABLE_HTTP
 
-#define DSIZ CURL_MAX_WRITE_SIZE /* buffer size for decompressed data */
-
+#define DECOMPRESS_BUFFER_SIZE 16384 /* buffer size for decompressed data */
 
 #ifdef HAVE_LIBZ
 
-/* Comment this out if zlib is always going to be at least ver. 1.2.0.4
-   (doing so will reduce code size slightly). */
-#define OLD_ZLIB_SUPPORT 1
-
-#define GZIP_MAGIC_0 0x1f
-#define GZIP_MAGIC_1 0x8b
-
-/* gzip flag byte */
-#define ASCII_FLAG   0x01 /* bit 0 set: file probably ascii text */
-#define HEAD_CRC     0x02 /* bit 1 set: header CRC present */
-#define EXTRA_FIELD  0x04 /* bit 2 set: extra field present */
-#define ORIG_NAME    0x08 /* bit 3 set: original file name present */
-#define COMMENT      0x10 /* bit 4 set: file comment present */
-#define RESERVED     0xE0 /* bits 5..7: reserved */
-
 typedef enum {
   ZLIB_UNINIT,               /* uninitialized */
   ZLIB_INIT,                 /* initialized */
   ZLIB_INFLATING,            /* inflating started. */
   ZLIB_EXTERNAL_TRAILER,     /* reading external trailer */
-  ZLIB_GZIP_HEADER,          /* reading gzip header */
-  ZLIB_GZIP_INFLATING,       /* inflating gzip stream */
   ZLIB_INIT_GZIP             /* initialized in transparent gzip mode */
 } zlibInitState;
 
@@ -94,6 +76,7 @@ typedef enum {
 struct zlib_writer {
   struct contenc_writer super;
   zlibInitState zlib_init;   /* zlib init state */
+  char buffer[DECOMPRESS_BUFFER_SIZE]; /* Put the decompressed data here. */
   uInt trailerlen;           /* Remaining trailer byte count. */
   z_stream z;                /* State structure for zlib. */
 };
@@ -131,9 +114,6 @@ static CURLcode
 exit_zlib(struct Curl_easy *data,
           z_stream *z, zlibInitState *zlib_init, CURLcode result)
 {
-  if(*zlib_init == ZLIB_GZIP_HEADER)
-    Curl_safefree(z->next_in);
-
   if(*zlib_init != ZLIB_UNINIT) {
     if(inflateEnd(z) != Z_OK && result == CURLE_OK)
       result = process_zlib_error(data, z);
@@ -177,21 +157,13 @@ static CURLcode inflate_stream(struct Cu
   Bytef *orig_in = z->next_in;
   bool done = FALSE;
   CURLcode result = CURLE_OK;   /* Curl_client_write status */
-  char *decomp;                 /* Put the decompressed data here. */
 
   /* Check state. */
   if(zp->zlib_init != ZLIB_INIT &&
      zp->zlib_init != ZLIB_INFLATING &&
-     zp->zlib_init != ZLIB_INIT_GZIP &&
-     zp->zlib_init != ZLIB_GZIP_INFLATING)
+     zp->zlib_init != ZLIB_INIT_GZIP)
     return exit_zlib(data, z, &zp->zlib_init, CURLE_WRITE_ERROR);
 
-  /* Dynamically allocate a buffer for decompression because it's uncommonly
-     large to hold on the stack */
-  decomp = malloc(DSIZ);
-  if(!decomp)
-    return exit_zlib(data, z, &zp->zlib_init, CURLE_OUT_OF_MEMORY);
-
   /* because the buffer size is fixed, iteratively decompress and transfer to
      the client via downstream_write function. */
   while(!done) {
@@ -199,8 +171,8 @@ static CURLcode inflate_stream(struct Cu
     done = TRUE;
 
     /* (re)set buffer for decompressed output for every iteration */
-    z->next_out = (Bytef *) decomp;
-    z->avail_out = DSIZ;
+    z->next_out = (Bytef *) zp->buffer;
+    z->avail_out = DECOMPRESS_BUFFER_SIZE;
 
 #ifdef Z_BLOCK
     /* Z_BLOCK is only available in zlib ver. >= 1.2.0.5 */
@@ -211,11 +183,11 @@ static CURLcode inflate_stream(struct Cu
 #endif
 
     /* Flush output data if some. */
-    if(z->avail_out != DSIZ) {
+    if(z->avail_out != DECOMPRESS_BUFFER_SIZE) {
       if(status == Z_OK || status == Z_STREAM_END) {
         zp->zlib_init = started;      /* Data started. */
-        result = Curl_unencode_write(data, writer->downstream, decomp,
-                                     DSIZ - z->avail_out);
+        result = Curl_unencode_write(data, writer->downstream, zp->buffer,
+                                     DECOMPRESS_BUFFER_SIZE - z->avail_out);
         if(result) {
           exit_zlib(data, z, &zp->zlib_init, result);
           break;
@@ -258,7 +230,6 @@ static CURLcode inflate_stream(struct Cu
       break;
     }
   }
-  free(decomp);
 
   /* We're about to leave this call so the `nread' data bytes won't be seen
      again. If we are in a state that would wrongly allow restart in raw mode
@@ -333,6 +304,7 @@ static CURLcode gzip_init_writer(struct
 {
   struct zlib_writer *zp = (struct zlib_writer *) writer;
   z_stream *z = &zp->z;     /* zlib state structure */
+  const char *v = zlibVersion();
 
   if(!writer->downstream)
     return CURLE_WRITE_ERROR;
@@ -341,109 +313,21 @@ static CURLcode gzip_init_writer(struct
   z->zalloc = (alloc_func) zalloc_cb;
   z->zfree = (free_func) zfree_cb;
 
-  if(strcmp(zlibVersion(), "1.2.0.4") >= 0) {
-    /* zlib ver. >= 1.2.0.4 supports transparent gzip decompressing */
+  if(strcmp(v, "1.2.0.4") >= 0) {
+    /* zlib version >= 1.2.0.4 supports transparent gzip decompressing */
     if(inflateInit2(z, MAX_WBITS + 32) != Z_OK) {
       return process_zlib_error(data, z);
     }
     zp->zlib_init = ZLIB_INIT_GZIP; /* Transparent gzip decompress state */
   }
   else {
-    /* we must parse the gzip header and trailer ourselves */
-    if(inflateInit2(z, -MAX_WBITS) != Z_OK) {
-      return process_zlib_error(data, z);
-    }
-    zp->trailerlen = 8; /* A CRC-32 and a 32-bit input size (RFC 1952, 2.2) */
-    zp->zlib_init = ZLIB_INIT; /* Initial call state */
+    failf(data, "too old zlib version: %s", v);
+    return CURLE_FAILED_INIT;
   }
 
   return CURLE_OK;
 }
 
-#ifdef OLD_ZLIB_SUPPORT
-/* Skip over the gzip header */
-static enum {
-  GZIP_OK,
-  GZIP_BAD,
-  GZIP_UNDERFLOW
-} check_gzip_header(unsigned char const *data, ssize_t len, ssize_t *headerlen)
-{
-  int method, flags;
-  const ssize_t totallen = len;
-
-  /* The shortest header is 10 bytes */
-  if(len < 10)
-    return GZIP_UNDERFLOW;
-
-  if((data[0] != GZIP_MAGIC_0) || (data[1] != GZIP_MAGIC_1))
-    return GZIP_BAD;
-
-  method = data[2];
-  flags = data[3];
-
-  if(method != Z_DEFLATED || (flags & RESERVED) != 0) {
-    /* Can't handle this compression method or unknown flag */
-    return GZIP_BAD;
-  }
-
-  /* Skip over time, xflags, OS code and all previous bytes */
-  len -= 10;
-  data += 10;
-
-  if(flags & EXTRA_FIELD) {
-    ssize_t extra_len;
-
-    if(len < 2)
-      return GZIP_UNDERFLOW;
-
-    extra_len = (data[1] << 8) | data[0];
-
-    if(len < (extra_len + 2))
-      return GZIP_UNDERFLOW;
-
-    len -= (extra_len + 2);
-    data += (extra_len + 2);
-  }
-
-  if(flags & ORIG_NAME) {
-    /* Skip over NUL-terminated file name */
-    while(len && *data) {
-      --len;
-      ++data;
-    }
-    if(!len || *data)
-      return GZIP_UNDERFLOW;
-
-    /* Skip over the NUL */
-    --len;
-    ++data;
-  }
-
-  if(flags & COMMENT) {
-    /* Skip over NUL-terminated comment */
-    while(len && *data) {
-      --len;
-      ++data;
-    }
-    if(!len || *data)
-      return GZIP_UNDERFLOW;
-
-    /* Skip over the NUL */
-    --len;
-  }
-
-  if(flags & HEAD_CRC) {
-    if(len < 2)
-      return GZIP_UNDERFLOW;
-
-    len -= 2;
-  }
-
-  *headerlen = totallen - len;
-  return GZIP_OK;
-}
-#endif
-
 static CURLcode gzip_unencode_write(struct Curl_easy *data,
                                     struct contenc_writer *writer,
                                     const char *buf, size_t nbytes)
@@ -459,117 +343,8 @@ static CURLcode gzip_unencode_write(stru
     return inflate_stream(data, writer, ZLIB_INIT_GZIP);
   }
 
-#ifndef OLD_ZLIB_SUPPORT
-  /* Support for old zlib versions is compiled away and we are running with
-     an old version, so return an error. */
+  /* We are running with an old version: return error. */
   return exit_zlib(data, z, &zp->zlib_init, CURLE_WRITE_ERROR);
-
-#else
-  /* This next mess is to get around the potential case where there isn't
-   * enough data passed in to skip over the gzip header.  If that happens, we
-   * malloc a block and copy what we have then wait for the next call.  If
-   * there still isn't enough (this is definitely a worst-case scenario), we
-   * make the block bigger, copy the next part in and keep waiting.
-   *
-   * This is only required with zlib versions < 1.2.0.4 as newer versions
-   * can handle the gzip header themselves.
-   */
-
-  switch(zp->zlib_init) {
-  /* Skip over gzip header? */
-  case ZLIB_INIT:
-  {
-    /* Initial call state */
-    ssize_t hlen;
-
-    switch(check_gzip_header((unsigned char *) buf, nbytes, &hlen)) {
-    case GZIP_OK:
-      z->next_in = (Bytef *) buf + hlen;
-      z->avail_in = (uInt) (nbytes - hlen);
-      zp->zlib_init = ZLIB_GZIP_INFLATING; /* Inflating stream state */
-      break;
-
-    case GZIP_UNDERFLOW:
-      /* We need more data so we can find the end of the gzip header.  It's
-       * possible that the memory block we malloc here will never be freed if
-       * the transfer abruptly aborts after this point.  Since it's unlikely
-       * that circumstances will be right for this code path to be followed in
-       * the first place, and it's even more unlikely for a transfer to fail
-       * immediately afterwards, it should seldom be a problem.
-       */
-      z->avail_in = (uInt) nbytes;
-      z->next_in = malloc(z->avail_in);
-      if(!z->next_in) {
-        return exit_zlib(data, z, &zp->zlib_init, CURLE_OUT_OF_MEMORY);
-      }
-      memcpy(z->next_in, buf, z->avail_in);
-      zp->zlib_init = ZLIB_GZIP_HEADER;  /* Need more gzip header data state */
-      /* We don't have any data to inflate yet */
-      return CURLE_OK;
-
-    case GZIP_BAD:
-    default:
-      return exit_zlib(data, z, &zp->zlib_init, process_zlib_error(data, z));
-    }
-
-  }
-  break;
-
-  case ZLIB_GZIP_HEADER:
-  {
-    /* Need more gzip header data state */
-    ssize_t hlen;
-    z->avail_in += (uInt) nbytes;
-    z->next_in = Curl_saferealloc(z->next_in, z->avail_in);
-    if(!z->next_in) {
-      return exit_zlib(data, z, &zp->zlib_init, CURLE_OUT_OF_MEMORY);
-    }
-    /* Append the new block of data to the previous one */
-    memcpy(z->next_in + z->avail_in - nbytes, buf, nbytes);
-
-    switch(check_gzip_header(z->next_in, z->avail_in, &hlen)) {
-    case GZIP_OK:
-      /* This is the zlib stream data */
-      free(z->next_in);
-      /* Don't point into the malloced block since we just freed it */
-      z->next_in = (Bytef *) buf + hlen + nbytes - z->avail_in;
-      z->avail_in = (uInt) (z->avail_in - hlen);
-      zp->zlib_init = ZLIB_GZIP_INFLATING;   /* Inflating stream state */
-      break;
-
-    case GZIP_UNDERFLOW:
-      /* We still don't have any data to inflate! */
-      return CURLE_OK;
-
-    case GZIP_BAD:
-    default:
-      return exit_zlib(data, z, &zp->zlib_init, process_zlib_error(data, z));
-    }
-
-  }
-  break;
-
-  case ZLIB_EXTERNAL_TRAILER:
-    z->next_in = (Bytef *) buf;
-    z->avail_in = (uInt) nbytes;
-    return process_trailer(data, zp);
-
-  case ZLIB_GZIP_INFLATING:
-  default:
-    /* Inflating stream state */
-    z->next_in = (Bytef *) buf;
-    z->avail_in = (uInt) nbytes;
-    break;
-  }
-
-  if(z->avail_in == 0) {
-    /* We don't have any data to inflate; wait until next time */
-    return CURLE_OK;
-  }
-
-  /* We've parsed the header, now uncompress the data */
-  return inflate_stream(data, writer, ZLIB_GZIP_INFLATING);
-#endif
 }
 
 static void gzip_close_writer(struct Curl_easy *data,
@@ -597,6 +372,7 @@ static const struct content_encoding gzi
 /* Brotli writer. */
 struct brotli_writer {
   struct contenc_writer super;
+  char buffer[DECOMPRESS_BUFFER_SIZE];
   BrotliDecoderState *br;    /* State structure for brotli. */
 };
 
@@ -657,7 +433,6 @@ static CURLcode brotli_unencode_write(st
 {
   struct brotli_writer *bp = (struct brotli_writer *) writer;
   const uint8_t *src = (const uint8_t *) buf;
-  char *decomp;
   uint8_t *dst;
   size_t dstleft;
   CURLcode result = CURLE_OK;
@@ -666,18 +441,14 @@ static CURLcode brotli_unencode_write(st
   if(!bp->br)
     return CURLE_WRITE_ERROR;  /* Stream already ended. */
 
-  decomp = malloc(DSIZ);
-  if(!decomp)
-    return CURLE_OUT_OF_MEMORY;
-
   while((nbytes || r == BROTLI_DECODER_RESULT_NEEDS_MORE_OUTPUT) &&
         result == CURLE_OK) {
-    dst = (uint8_t *) decomp;
-    dstleft = DSIZ;
+    dst = (uint8_t *) bp->buffer;
+    dstleft = DECOMPRESS_BUFFER_SIZE;
     r = BrotliDecoderDecompressStream(bp->br,
                                       &nbytes, &src, &dstleft, &dst, NULL);
     result = Curl_unencode_write(data, writer->downstream,
-                                 decomp, DSIZ - dstleft);
+                                 bp->buffer, DECOMPRESS_BUFFER_SIZE - dstleft);
     if(result)
       break;
     switch(r) {
@@ -695,7 +466,6 @@ static CURLcode brotli_unencode_write(st
       break;
     }
   }
-  free(decomp);
   return result;
 }
 
@@ -728,7 +498,7 @@ static const struct content_encoding bro
 struct zstd_writer {
   struct contenc_writer super;
   ZSTD_DStream *zds;    /* State structure for zstd. */
-  void *decomp;
+  char buffer[DECOMPRESS_BUFFER_SIZE];
 };
 
 static CURLcode zstd_init_writer(struct Curl_easy *data,
@@ -742,7 +512,6 @@ static CURLcode zstd_init_writer(struct
     return CURLE_WRITE_ERROR;
 
   zp->zds = ZSTD_createDStream();
-  zp->decomp = NULL;
   return zp->zds ? CURLE_OK : CURLE_OUT_OF_MEMORY;
 }
 
@@ -756,19 +525,14 @@ static CURLcode zstd_unencode_write(stru
   ZSTD_outBuffer out;
   size_t errorCode;
 
-  if(!zp->decomp) {
-    zp->decomp = malloc(DSIZ);
-    if(!zp->decomp)
-      return CURLE_OUT_OF_MEMORY;
-  }
   in.pos = 0;
   in.src = buf;
   in.size = nbytes;
 
   for(;;) {
     out.pos = 0;
-    out.dst = zp->decomp;
-    out.size = DSIZ;
+    out.dst = zp->buffer;
+    out.size = DECOMPRESS_BUFFER_SIZE;
 
     errorCode = ZSTD_decompressStream(zp->zds, &out, &in);
     if(ZSTD_isError(errorCode)) {
@@ -776,7 +540,7 @@ static CURLcode zstd_unencode_write(stru
     }
     if(out.pos > 0) {
       result = Curl_unencode_write(data, writer->downstream,
-                                   zp->decomp, out.pos);
+                                   zp->buffer, out.pos);
       if(result)
         break;
     }
@@ -794,10 +558,6 @@ static void zstd_close_writer(struct Cur
 
   (void)data;
 
-  if(zp->decomp) {
-    free(zp->decomp);
-    zp->decomp = NULL;
-  }
   if(zp->zds) {
     ZSTD_freeDStream(zp->zds);
     zp->zds = NULL;
@@ -951,17 +711,15 @@ static CURLcode error_unencode_write(str
                                      struct contenc_writer *writer,
                                      const char *buf, size_t nbytes)
 {
-  char *all = Curl_all_content_encodings();
-
   (void) writer;
   (void) buf;
   (void) nbytes;
 
-  if(!all)
-    return CURLE_OUT_OF_MEMORY;
+  char all[256];
+  (void)Curl_all_content_encodings();
   failf(data, "Unrecognized content encoding type. "
         "libcurl understands %s content encodings.", all);
-  free(all);
+
   return CURLE_BAD_CONTENT_ENCODING;
 }
 
@@ -1049,7 +807,7 @@ static const struct content_encoding *fi
 /* allow no more than 5 "chained" compression steps */
 #define MAX_ENCODE_STACK 5
 
-/* Set-up the unencoding stack from the Content-Encoding header value.
+/* Setup the unencoding stack from the Content-Encoding header value.
  * See RFC 7231 section 3.1.2.2. */
 CURLcode Curl_build_unencoding_stack(struct Curl_easy *data,
                                      const char *enclist, int is_transfer)
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