482 lines
14 KiB
Diff
482 lines
14 KiB
Diff
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From d47f6aec436e0e9df6554436e391471097686ecc Mon Sep 17 00:00:00 2001
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From: Michael R Sweet <michael.r.sweet@gmail.com>
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Date: Tue, 8 May 2018 15:24:21 -0700
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Subject: [PATCH] Fix local privilege escalation to root and sandbox bypasses
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in scheduler (rdar://37836779, rdar://37836995, rdar://37837252,
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rdar://37837581)
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---
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man/cups-files.conf.man.in | 10 ++
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man/cupsd.conf.man.in | 8 --
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scheduler/conf.c | 201 +++++++++++++++++++++++--------------
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scheduler/job.c | 12 +++
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scheduler/process.c | 16 +--
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scheduler/server.c | 20 +++-
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test/run-stp-tests.sh | 11 +-
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7 files changed, 179 insertions(+), 99 deletions(-)
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diff --git a/man/cups-files.conf.man.in b/man/cups-files.conf.man.in
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index 7b96d687d..baf3cb6af 100644
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--- a/man/cups-files.conf.man.in
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+++ b/man/cups-files.conf.man.in
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@@ -153,6 +153,11 @@ The server name may be included in filenames using the string "%s", for example:
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.fi
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The default is "/var/log/cups/page_log".
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+.\"#PassEnv
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+.TP 5
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+\fBPassEnv \fIvariable \fR[ ... \fIvariable \fR]
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+Passes the specified environment variable(s) to child processes.
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+Note: the standard CUPS filter and backend environment variables cannot be overridden using this directive.
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.\"#RemoteRoot
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.TP 5
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\fBRemoteRoot \fIusername\fR
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@@ -187,6 +192,11 @@ macOS uses its keychain database to store certificates and keys while other plat
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\fBServerRoot \fIdirectory\fR
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Specifies the directory containing the server configuration files.
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The default is "/etc/cups".
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+.\"#SetEnv
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+.TP 5
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+\fBSetEnv \fIvariable value\fR
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+Set the specified environment variable to be passed to child processes.
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+Note: the standard CUPS filter and backend environment variables cannot be overridden using this directive.
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.\"#StateDir
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.TP 5
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\fBStateDir \fIdirectory\fR
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diff --git a/man/cupsd.conf.man.in b/man/cupsd.conf.man.in
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index 3ffc80e42..36c849398 100644
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--- a/man/cupsd.conf.man.in
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+++ b/man/cupsd.conf.man.in
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@@ -349,10 +349,6 @@ The default is "1048576" (1MB).
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\fBMultipleOperationTimeout \fIseconds\fR
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Specifies the maximum amount of time to allow between files in a multiple file print job.
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The default is "300" (5 minutes).
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-.\"#PassEnv
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-.TP 5
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-\fBPassEnv \fIvariable \fR[ ... \fIvariable \fR]
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-Passes the specified environment variable(s) to child processes.
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.\"#Policy
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.TP 5
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\fB<Policy \fIname\fB> \fR... \fB</Policy>\fR
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@@ -433,10 +429,6 @@ Specifies what information is included in the Server header of HTTP responses.
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command.
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"Full" reports "CUPS 2.0.0 (UNAME) IPP/2.0".
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The default is "Minimal".
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-.\"#SetEnv
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-.TP 5
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-\fBSetEnv \fIvariable value\fR
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-Set the specified environment variable to be passed to child processes.
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.\"#SSLListen
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.TP 5
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\fBSSLListen \fIipv4-address\fB:\fIport\fR
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diff --git a/scheduler/conf.c b/scheduler/conf.c
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index 67a91e7a6..b51c6060c 100644
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--- a/scheduler/conf.c
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+++ b/scheduler/conf.c
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@@ -2929,13 +2929,10 @@ read_cupsd_conf(cups_file_t *fp) /* I - File to read from */
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/* Line from file */
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temp[HTTP_MAX_BUFFER],
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/* Temporary buffer for value */
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- *value, /* Pointer to value */
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- *valueptr; /* Pointer into value */
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+ *value; /* Pointer to value */
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int valuelen; /* Length of value */
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http_addrlist_t *addrlist, /* Address list */
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*addr; /* Current address */
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- cups_file_t *incfile; /* Include file */
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- char incname[1024]; /* Include filename */
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/*
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@@ -2950,28 +2947,7 @@ read_cupsd_conf(cups_file_t *fp) /* I - File to read from */
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* Decode the directive...
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*/
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- if (!_cups_strcasecmp(line, "Include") && value)
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- {
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- /*
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- * Include filename
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- */
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-
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- if (value[0] == '/')
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- strlcpy(incname, value, sizeof(incname));
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- else
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- snprintf(incname, sizeof(incname), "%s/%s", ServerRoot, value);
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-
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- if ((incfile = cupsFileOpen(incname, "rb")) == NULL)
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- cupsdLogMessage(CUPSD_LOG_ERROR,
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- "Unable to include config file \"%s\" - %s",
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- incname, strerror(errno));
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- else
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- {
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- read_cupsd_conf(incfile);
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- cupsFileClose(incfile);
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- }
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- }
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- else if (!_cups_strcasecmp(line, "<Location") && value)
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+ if (!_cups_strcasecmp(line, "<Location") && value)
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{
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/*
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* <Location path>
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@@ -3367,31 +3343,6 @@ read_cupsd_conf(cups_file_t *fp) /* I - File to read from */
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cupsdLogMessage(CUPSD_LOG_WARN, "Unknown ServerTokens %s on line %d of %s.",
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value, linenum, ConfigurationFile);
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}
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- else if (!_cups_strcasecmp(line, "PassEnv") && value)
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- {
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- /*
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- * PassEnv variable [... variable]
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- */
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-
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- for (; *value;)
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- {
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- for (valuelen = 0; value[valuelen]; valuelen ++)
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- if (_cups_isspace(value[valuelen]) || value[valuelen] == ',')
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- break;
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-
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- if (value[valuelen])
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- {
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- value[valuelen] = '\0';
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- valuelen ++;
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- }
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-
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- cupsdSetEnv(value, NULL);
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-
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- for (value += valuelen; *value; value ++)
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- if (!_cups_isspace(*value) || *value != ',')
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- break;
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- }
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- }
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else if (!_cups_strcasecmp(line, "ServerAlias") && value)
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{
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/*
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@@ -3420,30 +3371,6 @@ read_cupsd_conf(cups_file_t *fp) /* I - File to read from */
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break;
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}
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}
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- else if (!_cups_strcasecmp(line, "SetEnv") && value)
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- {
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- /*
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- * SetEnv variable value
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- */
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-
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- for (valueptr = value; *valueptr && !isspace(*valueptr & 255); valueptr ++);
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-
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- if (*valueptr)
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- {
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- /*
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- * Found a value...
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- */
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-
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- while (isspace(*valueptr & 255))
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- *valueptr++ = '\0';
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-
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- cupsdSetEnv(value, valueptr);
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- }
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- else
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- cupsdLogMessage(CUPSD_LOG_ERROR,
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- "Missing value for SetEnv directive on line %d of %s.",
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- linenum, ConfigurationFile);
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- }
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else if (!_cups_strcasecmp(line, "AccessLog") ||
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!_cups_strcasecmp(line, "CacheDir") ||
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!_cups_strcasecmp(line, "ConfigFilePerm") ||
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@@ -3457,6 +3384,7 @@ read_cupsd_conf(cups_file_t *fp) /* I - File to read from */
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!_cups_strcasecmp(line, "LogFilePerm") ||
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!_cups_strcasecmp(line, "LPDConfigFile") ||
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!_cups_strcasecmp(line, "PageLog") ||
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+ !_cups_strcasecmp(line, "PassEnv") ||
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!_cups_strcasecmp(line, "Printcap") ||
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!_cups_strcasecmp(line, "PrintcapFormat") ||
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!_cups_strcasecmp(line, "RemoteRoot") ||
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@@ -3466,6 +3394,7 @@ read_cupsd_conf(cups_file_t *fp) /* I - File to read from */
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!_cups_strcasecmp(line, "ServerKey") ||
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!_cups_strcasecmp(line, "ServerKeychain") ||
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!_cups_strcasecmp(line, "ServerRoot") ||
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+ !_cups_strcasecmp(line, "SetEnv") ||
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!_cups_strcasecmp(line, "SMBConfigFile") ||
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!_cups_strcasecmp(line, "StateDir") ||
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!_cups_strcasecmp(line, "SystemGroup") ||
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@@ -3495,10 +3424,49 @@ read_cupsd_conf(cups_file_t *fp) /* I - File to read from */
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static int /* O - 1 on success, 0 on failure */
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read_cups_files_conf(cups_file_t *fp) /* I - File to read from */
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{
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- int linenum; /* Current line number */
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+ int i, /* Looping var */
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+ linenum; /* Current line number */
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char line[HTTP_MAX_BUFFER], /* Line from file */
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*value; /* Value from line */
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struct group *group; /* Group */
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+ static const char * const prohibited_env[] =
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+ { /* Prohibited environment variables */
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+ "APPLE_LANGUAGE",
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+ "AUTH_DOMAIN",
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+ "AUTH_INFO_REQUIRED",
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+ "AUTH_NEGOTIATE",
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+ "AUTH_PASSWORD",
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+ "AUTH_UID",
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+ "AUTH_USERNAME",
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+ "CHARSET",
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+ "CLASS",
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+ "CLASSIFICATION",
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+ "CONTENT_TYPE",
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+ "CUPS_CACHEDIR",
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+ "CUPS_DATADIR",
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+ "CUPS_DOCROOT",
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+ "CUPS_FILETYPE",
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+ "CUPS_FONTPATH",
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+ "CUPS_MAX_MESSAGE",
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+ "CUPS_REQUESTROOT",
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+ "CUPS_SERVERBIN",
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+ "CUPS_SERVERROOT",
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+ "CUPS_STATEDIR",
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+ "DEVICE_URI",
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+ "FINAL_CONTENT_TYPE",
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+ "HOME",
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+ "LANG",
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+ "PPD",
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+ "PRINTER",
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+ "PRINTER_INFO",
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+ "PRINTER_LOCATION",
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+ "PRINTER_STATE_REASONS",
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+ "RIP_CACHE",
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+ "SERVER_ADMIN",
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+ "SOFTWARE",
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+ "TMPDIR",
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+ "USER"
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+ };
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/*
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@@ -3536,6 +3504,47 @@ read_cups_files_conf(cups_file_t *fp) /* I - File to read from */
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}
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}
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}
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+ else if (!_cups_strcasecmp(line, "PassEnv") && value)
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+ {
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+ /*
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+ * PassEnv variable [... variable]
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+ */
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+
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+ int valuelen; /* Length of variable name */
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+
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+ for (; *value;)
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+ {
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+ for (valuelen = 0; value[valuelen]; valuelen ++)
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+ if (_cups_isspace(value[valuelen]) || value[valuelen] == ',')
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+ break;
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+
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+ if (value[valuelen])
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+ {
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+ value[valuelen] = '\0';
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+ valuelen ++;
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+ }
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+
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+ for (i = 0; i < (int)(sizeof(prohibited_env) / sizeof(prohibited_env[0])); i ++)
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+ {
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+ if (!strcmp(value, prohibited_env[i]))
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+ {
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+ cupsdLogMessage(CUPSD_LOG_ERROR, "Environment variable \"%s\" cannot be passed through on line %d of %s.", value, linenum, CupsFilesFile);
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+
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+ if (FatalErrors & CUPSD_FATAL_CONFIG)
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+ return (0);
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+ else
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+ break;
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+ }
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+ }
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+
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+ if (i >= (int)(sizeof(prohibited_env) / sizeof(prohibited_env[0])))
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+ cupsdSetEnv(value, NULL);
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+
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+ for (value += valuelen; *value; value ++)
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+ if (!_cups_isspace(*value) || *value != ',')
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+ break;
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+ }
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+ }
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else if (!_cups_strcasecmp(line, "PrintcapFormat") && value)
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{
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/*
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@@ -3581,6 +3590,46 @@ read_cups_files_conf(cups_file_t *fp) /* I - File to read from */
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return (0);
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}
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}
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+ else if (!_cups_strcasecmp(line, "SetEnv") && value)
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+ {
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+ /*
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+ * SetEnv variable value
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+ */
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+
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+ char *valueptr; /* Pointer to environment variable value */
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+
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+ for (valueptr = value; *valueptr && !isspace(*valueptr & 255); valueptr ++);
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+
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+ if (*valueptr)
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+ {
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+ /*
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+ * Found a value...
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+ */
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+
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+ while (isspace(*valueptr & 255))
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+ *valueptr++ = '\0';
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+
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+ for (i = 0; i < (int)(sizeof(prohibited_env) / sizeof(prohibited_env[0])); i ++)
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+ {
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+ if (!strcmp(value, prohibited_env[i]))
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+ {
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+ cupsdLogMessage(CUPSD_LOG_ERROR, "Environment variable \"%s\" cannot be set on line %d of %s.", value, linenum, CupsFilesFile);
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+
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+ if (FatalErrors & CUPSD_FATAL_CONFIG)
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+ return (0);
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+ else
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+ break;
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+ }
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+ }
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+
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+ if (i >= (int)(sizeof(prohibited_env) / sizeof(prohibited_env[0])))
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+ cupsdSetEnv(value, valueptr);
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+ }
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+ else
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+ cupsdLogMessage(CUPSD_LOG_ERROR,
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+ "Missing value for SetEnv directive on line %d of %s.",
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+ linenum, ConfigurationFile);
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+ }
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else if (!_cups_strcasecmp(line, "SystemGroup") && value)
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{
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/*
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diff --git a/scheduler/job.c b/scheduler/job.c
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index 61cda44e2..5ced0b9d1 100644
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--- a/scheduler/job.c
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+++ b/scheduler/job.c
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@@ -4779,6 +4779,18 @@ start_job(cupsd_job_t *job, /* I - Job ID */
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job->profile = cupsdCreateProfile(job->id, 0);
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job->bprofile = cupsdCreateProfile(job->id, 1);
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+#ifdef HAVE_SANDBOX_H
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+ if ((!job->profile || !job->bprofile) && UseSandboxing && Sandboxing != CUPSD_SANDBOXING_OFF)
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+ {
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+ /*
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+ * Failure to create the sandbox profile means something really bad has
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+ * happened and we need to shutdown immediately.
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+ */
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+
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+ return;
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+ }
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+#endif /* HAVE_SANDBOX_H */
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+
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/*
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* Create the status pipes and buffer...
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*/
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diff --git a/scheduler/process.c b/scheduler/process.c
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index b8d49d8f0..3c1c6ba4f 100644
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--- a/scheduler/process.c
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+++ b/scheduler/process.c
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@@ -98,9 +98,13 @@ cupsdCreateProfile(int job_id, /* I - Job ID or 0 for none */
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if ((fp = cupsTempFile2(profile, sizeof(profile))) == NULL)
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{
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+ /*
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+ * This should never happen, and is fatal when sandboxing is enabled.
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+ */
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+
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cupsdLogMessage(CUPSD_LOG_DEBUG2, "cupsdCreateProfile(job_id=%d, allow_networking=%d) = NULL", job_id, allow_networking);
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- cupsdLogMessage(CUPSD_LOG_ERROR, "Unable to create security profile: %s",
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- strerror(errno));
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+ cupsdLogMessage(CUPSD_LOG_EMERG, "Unable to create security profile: %s", strerror(errno));
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+ kill(getpid(), SIGTERM);
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return (NULL);
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}
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@@ -197,10 +201,8 @@ cupsdCreateProfile(int job_id, /* I - Job ID or 0 for none */
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" #\"^%s/\"" /* TempDir/... */
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" #\"^%s$\"" /* CacheDir */
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|
" #\"^%s/\"" /* CacheDir/... */
|
||
|
- " #\"^%s$\"" /* StateDir */
|
||
|
- " #\"^%s/\"" /* StateDir/... */
|
||
|
"))\n",
|
||
|
- temp, temp, cache, cache, state, state);
|
||
|
+ temp, temp, cache, cache);
|
||
|
/* Read common folders */
|
||
|
cupsFilePrintf(fp,
|
||
|
"(allow file-read-data file-read-metadata\n"
|
||
|
@@ -242,8 +244,10 @@ cupsdCreateProfile(int job_id, /* I - Job ID or 0 for none */
|
||
|
" #\"^%s/\"" /* ServerBin/... */
|
||
|
" #\"^%s$\"" /* ServerRoot */
|
||
|
" #\"^%s/\"" /* ServerRoot/... */
|
||
|
+ " #\"^%s$\"" /* StateDir */
|
||
|
+ " #\"^%s/\"" /* StateDir/... */
|
||
|
"))\n",
|
||
|
- request, request, bin, bin, root, root);
|
||
|
+ request, request, bin, bin, root, root, state, state);
|
||
|
if (Sandboxing == CUPSD_SANDBOXING_RELAXED)
|
||
|
{
|
||
|
/* Limited write access to /Library/Printers/... */
|
||
|
diff --git a/scheduler/server.c b/scheduler/server.c
|
||
|
index cecbabe67..a4033791b 100644
|
||
|
--- a/scheduler/server.c
|
||
|
+++ b/scheduler/server.c
|
||
|
@@ -34,16 +34,28 @@ void
|
||
|
cupsdStartServer(void)
|
||
|
{
|
||
|
/*
|
||
|
- * Start color management (as needed)...
|
||
|
+ * Create the default security profile...
|
||
|
*/
|
||
|
|
||
|
- cupsdStartColor();
|
||
|
+ DefaultProfile = cupsdCreateProfile(0, 1);
|
||
|
+
|
||
|
+#ifdef HAVE_SANDBOX_H
|
||
|
+ if (!DefaultProfile && UseSandboxing && Sandboxing != CUPSD_SANDBOXING_OFF)
|
||
|
+ {
|
||
|
+ /*
|
||
|
+ * Failure to create the sandbox profile means something really bad has
|
||
|
+ * happened and we need to shutdown immediately.
|
||
|
+ */
|
||
|
+
|
||
|
+ return;
|
||
|
+ }
|
||
|
+#endif /* HAVE_SANDBOX_H */
|
||
|
|
||
|
/*
|
||
|
- * Create the default security profile...
|
||
|
+ * Start color management (as needed)...
|
||
|
*/
|
||
|
|
||
|
- DefaultProfile = cupsdCreateProfile(0, 1);
|
||
|
+ cupsdStartColor();
|
||
|
|
||
|
/*
|
||
|
* Startup all the networking stuff...
|
||
|
diff --git a/test/run-stp-tests.sh b/test/run-stp-tests.sh
|
||
|
index 7eb269a67..f83bd5d91 100755
|
||
|
--- a/test/run-stp-tests.sh
|
||
|
+++ b/test/run-stp-tests.sh
|
||
|
@@ -489,11 +489,6 @@ StrictConformance Yes
|
||
|
Browsing Off
|
||
|
Listen localhost:$port
|
||
|
Listen $BASE/sock
|
||
|
-PassEnv DYLD_LIBRARY_PATH
|
||
|
-PassEnv LD_LIBRARY_PATH
|
||
|
-PassEnv LD_PRELOAD
|
||
|
-PassEnv LOCALEDIR
|
||
|
-PassEnv SHLIB_PATH
|
||
|
MaxSubscriptions 3
|
||
|
MaxLogSize 0
|
||
|
AccessLogLevel actions
|
||
|
@@ -529,6 +524,12 @@ TempDir $BASE/spool/temp
|
||
|
AccessLog $BASE/log/access_log
|
||
|
ErrorLog $BASE/log/error_log
|
||
|
PageLog $BASE/log/page_log
|
||
|
+
|
||
|
+PassEnv DYLD_LIBRARY_PATH
|
||
|
+PassEnv LD_LIBRARY_PATH
|
||
|
+PassEnv LD_PRELOAD
|
||
|
+PassEnv LOCALEDIR
|
||
|
+PassEnv SHLIB_PATH
|
||
|
EOF
|
||
|
|
||
|
if test $ssltype != 0 -a `uname` = Darwin; then
|
||
|
--
|
||
|
2.17.1
|
||
|
|