887e219f24
Resolves: CVE-2023-24805
108 lines
3.4 KiB
Diff
108 lines
3.4 KiB
Diff
diff --git a/backend/beh.c b/backend/beh.c
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index 225fd27..5e9cee0 100644
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--- a/backend/beh.c
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+++ b/backend/beh.c
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@@ -22,6 +22,7 @@
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#include "backend-private.h"
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#include <cups/array.h>
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#include <ctype.h>
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+#include <sys/wait.h>
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/*
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* Local globals...
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@@ -213,10 +214,14 @@ call_backend(char *uri, /* I - URI of final destination */
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char **argv, /* I - Command-line arguments */
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char *filename) { /* I - File name of input data */
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const char *cups_serverbin; /* Location of programs */
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+ char *backend_argv[8]; // Arguments for called CUPS backend
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char scheme[1024], /* Scheme from URI */
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*ptr, /* Pointer into scheme */
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- cmdline[65536]; /* Backend command line */
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- int retval;
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+ backend_path[2048]; // Backend path
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+ int pid,
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+ wait_pid,
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+ wait_status,
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+ retval = 0;
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/*
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* Build the backend command line...
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@@ -235,16 +240,19 @@ call_backend(char *uri, /* I - URI of final destination */
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fprintf(stderr,
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"ERROR: beh: Direct output into a file not supported.\n");
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exit (CUPS_BACKEND_FAILED);
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- } else
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- snprintf(cmdline, sizeof(cmdline),
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- "%s/backend/%s '%s' '%s' '%s' '%s' '%s' %s",
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- cups_serverbin, scheme, argv[1], argv[2], argv[3],
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- /* Apply number of copies only if beh was called with a
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- file name and not with the print data in stdin, as
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- backends should handle copies only if they are called
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- with a file name */
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- (argc == 6 ? "1" : argv[4]),
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- argv[5], filename);
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+ }
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+
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+ backend_argv[0] = uri;
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+ backend_argv[1] = argv[1];
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+ backend_argv[2] = argv[2];
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+ backend_argv[3] = argv[3];
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+ backend_argv[4] = (argc == 6 ? "1" : argv[4]);
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+ backend_argv[5] = argv[5];
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+ backend_argv[6] = filename;
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+ backend_argv[7] = NULL;
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+
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+ snprintf(backend_path, sizeof(backend_path),
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+ "%s/backend/%s", cups_serverbin, scheme);
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/*
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* Overwrite the device URI and run the actual backend...
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@@ -253,17 +261,41 @@ call_backend(char *uri, /* I - URI of final destination */
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setenv("DEVICE_URI", uri, 1);
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fprintf(stderr,
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- "DEBUG: beh: Executing backend command line \"%s\"...\n",
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- cmdline);
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+ "DEBUG: beh: Executing backend command line \"%s '%s' '%s' '%s' '%s' '%s'%s%s\"...\n",
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+ backend_path, backend_argv[1], backend_argv[2], backend_argv[3],
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+ backend_argv[4], backend_argv[5],
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+ (backend_argv[6] && backend_argv[6][0] ? " " : ""),
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+ (backend_argv[6] && backend_argv[6][0] ? backend_argv[6] : ""));
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fprintf(stderr,
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"DEBUG: beh: Using device URI: %s\n",
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uri);
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- retval = system(cmdline) >> 8;
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+ if ((pid = fork()) == 0)
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+ {
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+ retval = execv(backend_path, backend_argv);
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+
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+ if (retval == -1)
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+ fprintf(stderr, "ERROR: Unable to execute backend: %s\n",
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+ strerror(errno));
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+ exit (CUPS_BACKEND_FAILED);
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+ }
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+ else if (pid < 0)
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+ {
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+ fprintf(stderr, "ERROR: Unable to fork for backend\n");
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+ return (CUPS_BACKEND_FAILED);
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+ }
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+
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+ while ((wait_pid = wait(&wait_status)) < 0 && errno == EINTR);
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- if (retval == -1)
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- fprintf(stderr, "ERROR: Unable to execute backend command line: %s\n",
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- strerror(errno));
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+ if (wait_pid >= 0 && wait_status)
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+ {
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+ if (WIFEXITED(wait_status))
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+ retval = WEXITSTATUS(wait_status);
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+ else if (WTERMSIG(wait_status) != SIGTERM)
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+ retval = WTERMSIG(wait_status);
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+ else
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+ retval = 0;
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+ }
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return (retval);
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}
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